| Gastric cancer (GC) is one of the most common malignant tumors in the world withhigh morbidity and mortality in China. Invasion and metastasis are leading causes ofdeath. It is important for clinical therapy and prognosis to further study themechanisms of GC invasion and metastasis. Interleukin-1β (IL-1β) has beenimplicated in the progression of gastric adenocarcinoma (GA); however, themolecular mechanisms of action of IL-1β in GA are poorly characterized. P38is themajor MAPK family members that regulate IL-1β signaling pathways. Here, weinvestigated the role of p38in IL-1β-induced GA cell migration, invasion andmetastasis potential.Objective: To study the effect of p38in IL-1β-induced GA cell migration, invasionand metastasis and to explore its mechanism from the level of cell, clinical samplesand animal levels with the purposes to provide a novel therapeutic target for GA.Methods:1. Use the Western blot to investigate whether IL-1β was able to activate p38in GAcells.2. Use the siRNA technology, p38signal pathway inhibitor SB202190and transwellassays to detect the influence and effects of IL-1β-induced activation of p38on theinvasion and metastasis in GA cells.3. Use the siRNA technology, p38signal pathway inhibitor SB202190and RT-PCRto detect the influence and effects of IL-1β-induced activation of p38on mRNAexpression levels of MMP2, MMP9in GA cells.4. Use the siRNA technology and MMP2/MM9inhibitor BiPS to further test whetherthe IL-1β-induced GA cell migration, invasion and metastasis were involved inMMP2and MMP9.5. Use the immunohistochemistry to examine the expression of phosphorylated p38(p-p38) and the relationship between IL-1β, MMP2, MMP9expression in human GA tissues.6. Use the siRNA technology, animal experiment, RT-PCR assay and immunohisto-chemistry to detect the number of metastatic foci in nude mice and p38/(p-p38),MMP2, MMP9mRNA and protein expression in the lung metastases withknockdown p38and before and after IL-1β stimulates.Results:1. Activation of p38(p-p38) was detected in both GA cell lines (AGS and MKN-45cells) after treatment with IL-1β for30min; IL-1β-induced activation of p38wasinhibited by the p38inhibitor SB202190.2. IL-1β stimulation increased the migration and invasion of both AGS and MKN-45cells; however, IL-1β-induced GA cell migration and invasion were significantlyattenuated by knockdown of p38using siRNA or pretreatment cell withSB202190.3. MMP2and MMP9expression was elevated in response to IL-1β treatment.Knockdown of p38using siRNA, or pretreatment cell with the p38inhibitorSB202190significantly decreased IL-1β-induced MMP2and MMP9mRNAexpression in both GA cell lines.4. The IL-1β-induced migration and invasion of GA cells were significantlyattenuated by knockdown of MMP2or MMP9, or pre-treatment cell with BiPS,compared to control cells.5. Of the105cancer samples,53cases of GA tissues (50.48%) exhibitedover-expression of p-p38compared to the paired non-neoplastic gastric tissues.No significant associations were observed between overexpression of p-p38in thepatients’age, gender, tumor size, histological type, or grade of differentiation.However, overexpression of p-p38displayed significantly related with lymphnode metastasis and invasion beyond the serosa. Moreover, the expression ofp-p38showed good correlativity with the levels of IL-1β, MMP2and MMP9inGA tissue, and a significant correlation between the elevated p-p38expression andupregulation of IL-1β, MMP2and MMP9in GA tissue.6. In the metastasis assay in nude mice, the number of metastatic foci in nude mice were fewer in the p38siRNA plus IL-β-treated group (group3) or in the controlgroup (group1) compared to scramble siRNA plus IL-β-treated group (group2);The mRNA or protein expression levels of p38/p-p38, MMP2and MMP9werehigher in the scramble siRNA plus IL-β-treated group.Conclusions: IL-1β-induced activation of p38promotes invasion and metastasis ingastric adenocarcinoma (GA) via upregulation of MMP2and MMP9; this finding mayprovide a novel therapeutic target for GA. |
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