RESUMO
Cytokine-induced killer (CIK) cells have shown promising activity against gastric cancer in vitro and in vivo. Previous studies showed that cell signaling through MHC I-related Chain A (MICA)-Natural killer group 2, member D (NKG2D) results in CIK cell activation leading to cytolytic activities against tumor cells. In this study, we investigate the MICA status in patients with gastric carcinoma, and determine the potential relationship between MICA and clinical outcome of a CIK containing therapy. Two hundred and forty-three patients with gastric cancer who had received curative D2 gastrectomy were enrolled. The MICA expression of their tumors was determined by immunohistochemistry (IHC). Disease-free survival (DFS) and overall survival (OS) were evaluated. One hundred and forty-eight patients received adjuvant chemotherapy alone, and 95 patients received adjuvant chemotherapy combined with autologous CIK cell therapy. Patients who received adjuvant chemotherapy plus CIK had significantly longer DFS, 42.0 months vs. 32.0 months (P = 0.012), and OS, 45.0 months vs. 42.0 months (P = 0.039), by log-rank test. MICA high-expression, IHC scores of 5-7, was found in tumors from 89 of 243 patients (36.6%). The MICA expression was significantly correlated with the stage (P = 0.007) and there was a borderline association with histological grade (P = 0.054). In the adjuvant chemotherapy plus CIK group (n = 95), patients with high MICA expression had longer DFS, 46.0 months vs. 41.0 months (P = 0.027), and OS, 48.0 months vs. 42.0 months (P = 0.031). In the adjuvant chemotherapy alone group (n = 148), the median DFS and OS had no significant correlation with the MICA status. In a multivariate analysis stage, CIK therapy, and the interaction of MICA status and CIK therapy were independent prognostic factors for DFS and OS. Our study indicated that adjuvant chemotherapy plus CIK immunotherapy is a promising modality for treating gastric cancer patients after D2 gastrectomy. MICA status was associated with the outcome measures in CIK therapy, validation in prospective clinical trials is required to assess the value of this biomarker in the clinical decision-making process.
RESUMO
BACKGROUND AND OBJECTIVE: It has been proven that tumor necrosis factor receptor-associated factor 6 (TRAF6) was a commonly amplified oncogene in lung cancer. However, the precise role of TRAF6 protein in lung cancer has not been extensively investigated. This study analyzed the effects of TRAF6 on the proliferation, apoptosis, cell cycle, migration, and invasion capability of lung cancer cell lines, as well as the potential molecular mechanisms involved. METHODS: To address the expression of TRAF6 in lung cancer cells, four lung cancer cell lines (A549, H1650, SPC-A-1 and Calu-3) were assayed to determine the expression of TRAF6 protein by Western blot and TRAF6 mRNA via qRT-PCR. Moreover, siRNA targeting TRAF6 was introduced into SPC-A-1 and Calu-3 cells. Nuclear factor-ÒB (NF-ÒB) DNA-binding activity, apoptosis rates, cell proliferation, cell cycle, migration, and invasion were determined by electrophoretic mobility shift assay, flow cytometry, MTS assay, flow cytometry, scratch test, and transwell chamber assay, respectively. Western blot analysis was also performed to evaluate the expression of the following proteins through K63-ubiquitination: P65, CD24 and CXCR4. Whole-genome sequencing analysis was conducted using a second-generation sequencer in SPC-A-1 cells. RESULTS: TRAF6 was highly up-expressed in SPC-A-1 and Calu-3 cell lines than the other two cells, which also showed K63-ubiquitinization in TRAF6. However, constitutive activation of NF-ÒB was observed only in SPC-A-1 lung cancer cells. Downregulation of TRAF6 suppressed the NF-κB activation, cell migration, and invasion but promoted the cell apoptosis of SPC-A-1 cells. Markedly decreased expression of CD24 and CXCR4 was observed in SPC-A-1 cells transfected by TRAF6 siRNA. Nevertheless, TRAF6 downregulation did not affect the proliferation and cell cycle of SPC-A-1 cells. Additionally, TRAF6 regulation did not affect the proliferation, apoptosis, cell cycle, migration, and invasion of Calu-3 cells. No mutations and no changes in gene copy numbers of TRAF6 were found by whole-exome sequencing of SPC-A-1 cells. CONCLUSIONS: TRAF6 may be involved in cell migration, invasion, and apoptosis of SPC-A-1 cells, possibly through regulating the NF-ÒB-CD24/CXCR4 pathway.â©.