Silencing invariant chains of dendritic cells enhances anti-tumor immunity using small-interfering RNA / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Genetic modification of dendritic cells (DCs) has been used as an effective approach to enhance anti-tumor immunity. RNA interference (RNAi), which can cause the degradation of any RNA in a sequence-specific manner, is a post-transcriptional gene silencing mechanism. In this study, small-interfering RNA (siRNA) specific for the Ii gene was transfected into DCs, and the anti-tumor immunity of Ii-silenced DCs was assessed.</p><p><b>METHODS</b>The silencing effect of siRNA was evaluated by Western blotting and real-time PCR analyses. In vitro cytotoxic activity of T cells was evaluated using a Cytotox 96(®) non-radioactive cytotoxicity assay kit. The time to tumor onset and the tumor volumes were used as reliable indices to assess the anti-tumor immunity in vivo. To further examine the mechanisms underlying the anti-tumor immunity, flow cytometry analysis was used.</p><p><b>RESULTS</b>The Ii expression of DCs was significantly reduced after Ii siRNA transfection. Significant in vitro anti-tumor ability was exhibited when DCs were co-transfected with Ii siRNA plus endogenous tumor antigen (P < 0.05). Furthermore, tumor growth was greatly inhibited when mice were immunized with DCs transfected with Ii siRNA plus tumor antigen prior to or subsequent to tumor implantation. Flow cytometry analysis in vitro and in vivo indicated that both CD4(+) and CD8(+) T cells were significantly activated in the Ii siRNA group (P < 0.05).</p><p><b>CONCLUSION</b>Silencing of the Ii gene of DCs may offer a potential approach to enhance DC-based anti-tumor immunity.</p>

Inhibition of the proliferation of human gastric cancer cells SGC-7901 in vitro and in vivo using Bcl-2 siRNA / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Bcl-2, the anti-apoptotic protein is overexpressed in the majority of gastric cancers and associated with its pathogenesis. To better understanding of the role of Bcl-2, RNA interference (RNAi) was used to inhibit Bcl-2 expression in the human gastric cancer cells in vitro and in vivo.</p><p><b>METHODS</b>Bcl-2 small interfering RNA (siRNA) was transfected into human gastric cancer cells SGC-7901, and Bcl-2 expression was monitored by real-time polymerase chain reaction (PCR) and Western blot. Cell proliferation, apoptosis, and telomerase activity were examined by MTT, flow cytometry, and TRAP assay, respectively. Gastric cancer cells treated with 100 nmol/L Bcl-2 siRNA were subcutaneously transplanted into nude mice and tumor growth was assessed.</p><p><b>RESULTS</b>Bcl-2 siRNA significantly inhibited the expression of Bcl-2 in human gastric cancer cells at both mRNA and protein levels in a time- and dose-dependent manner. Bcl-2 siRNA also decreased telomerase activity (by 78.76%) and increased the rate of apoptosis (by 37.47%). SGC-7901 cell growth was also significantly suppressed in vivo and in vitro.</p><p><b>CONCLUSIONS</b>Bcl-2 expression knockdown suppressed the growth of gastric cancer cells. Thus, Bcl-2 may play a very important role in carcinogenesis of gastric cancer and its knockdown may offer a new potential gene therapy approach for human gastric cancer in future.</p>

Immunotherapeutic efficacy of both helper T lymphocytes and cytotoxic T lymphocytes epitopes augmented dendritic cells tumor vaccine on gastric cancer / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the immunotherapy efficacy of both helper T lymphocytes (Th) and cytotoxic T lymphocytes (CTL) epitopes augmented dendritic cells (DCs) tumor vaccine on gastric cancer.</p><p><b>METHODS</b>Naïve spleen T cells were stimulated by mixed peptides (a mixture of Th epitope MAGE-3 (22-36)) primed DCs per week in vitro. After 4 cycles of restimulation, peptide specific T cells were harvested and subgroups of which were determined with flow cytometry. Cytokines secreting profiles by CD4+ T cells and cytotoxicities of CD8+ T cells on tumor cells were assessed. The protective immunity by referred DCs tumor vaccines was also monitored.</p><p><b>RESULTS</b>Both Th and CTL epitopes primed DCs could elicit both CD4+ T cells and CD8+ T cells in vitro,of which CD4+ T cells released high amount of Th1 type cytokines (IFN-gamma, IL-2) on recognizing specific antigen, as well as CD8+ T cells exhibited efficient tumor-killing capacity. The effects induced by DCs pulsed with single epitope (Th or CTL epitope) in vivo were less effective than those induced by DCs pulsed with mixture epitopes.</p><p><b>CONCLUSIONS</b>Both Th and CTL epitopes augmented DCs tumor vaccine can induce CD4+ Th1 and CD8+ CTL mediated immune responses to eradicate gastric cancer cells.</p>

Identification of biomarkers in the serum of the patients with poorly differentiated gastric cancer / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the application of proteomics in the field of serology,and to screen the differential expression proteins related with poorly differentiated gastric carcinoma.</p><p><b>METHODS</b>Two-dimensional electrophoresis (2-DE) was applied to segregate the total proteins in the serum form gastric cancer patients and health volunteers. After staining,the differential expression proteins were analyzed using PDQuest software,and identified using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS).</p><p><b>RESULTS</b>Electrophoresis figures with high resolution and reproducibility were obtained. Six differential expression proteins were found only in the serum from gastric cancer patients, while four other proteins from healthy volunteers.</p><p><b>CONCLUSIONS</b>Protein expression is differential in the serum from the gastric cancer patients and health volunteers. It is hopeful to find the biomarkers related with poorly differentiated gastric carcinoma using proteomics.</p>

Expression of Ezrin in gastric carcinoma and its significance / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the expression of Ezrin in gastric cancer, its role in tumor metastasis.</p><p><b>METHODS</b>Ezrin expression in tumor tissues from 90 gastric cancer cases and in normal gastric mucosa from 12 cases with benign disease was examined by immunohistochemical staining. Ezrin expression in gastric cancer cell lines was also detected by Western blot, and in vitro invasion assay was used to examine the invasive ability of the cell lines.</p><p><b>RESULTS</b>The expression rate of Ezrin was significantly higher in gastric cancer tissues than that in normal tissues (P< 0.05), and significantly correlated with lymph node metastasis (P< 0.05). Western blot showed that MKN-45 cell line had the highest expression of Ezrin among 5 gastric cancer cells. MKN-45 possessed highest invasion ability.</p><p><b>CONCLUSION</b>Ezrin expression is up-regulated, and may be associated with lymph node metastasis in gastric cancer.</p>

Expression and clinical significance of cancer-related gene MPS-1 in gastric cancer / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the expression of cancer-related gene MPS-1 in gastric cancer and to evaluate its significance in clinical diagnosis and therapy.</p><p><b>METHODS</b>The mRNA expression of MPS-1 was determined by polymerase chain reaction after reverse transcription (RT-PCR) in cancer tissues and adjacent non-cancerous tissues from 42 cases with gastric cancer. The expression levels of MPS-1 in 6 gastric cancer cell lines (AGS, MKN-45, SGC 7901, KATO III, N-87 and SNU-1) were also determined by RT-PCR and Western blot.</p><p><b>RESULTS</b>The MPS-1 mRNA was expressed in all tissues and cell lines. The mRNA expression level of MPS-1 in cancer tissues were 1.37+/- 0.87, significantly higher than 0.99+/- 0.67 in adjacent normal gastric mucous tissues (P< 0.01). The expression of MPS-1 was correlated with TNM stage (P< 0.05), but not with age, gender, tumor size and differentiation. The expression level of MPS-1 mRNA in the primary lesions was hig her in the patients with TNM stages III, IV than those with TNM stages I, II. Meanwhile, RT-PCR and Western blot showed the same results that MPS-1 expression was higher in the six gastric cancer cell lines as compared with that in the normal gastric cell line GES-1.</p><p><b>CONCLUSION</b>The high expression of MPS-1 in gastric cancer indicates that MPS-1 might play an important role in gastric carcinogenesis,which may provide a new target in immunotherapy for gastric cancer.</p>