RBCK1 contributes to chemoresistance and stemness in colorectal cancer (CRC).

Chemotherapy is an essential treatment for colorectal cancer (CRC). However, colorectal cancer cells often develop resistance to chemotherapeutic drugs, resulting in relapse and poor patient prognosis. Growing studies indicate that tumor cells with stem cell-like features could promote resistance to chemotherapeutic agents. In this study, we demonstrated that RANBP2-type and C3HC4-type zinc finger-containing 1 (RBCK1) expression was markedly increased by cancer-associated fibroblasts (CAFs). First, we found that RBCK1 was over-expressed in chemoresistant CRC tumors and promoted chemoresistance in CRC cells. High RBCK1 expression was significantly correlated with poor prognosis in CRC patients. RBCK1 inhibition promoted sensitivity to chemotherapeutic drugs, and prevented migration and invasion in CRC cells. In addition, RBCK1 knockdown reduced cancer stemness by decreasing the expression of Nanog, Oct4, Sox2 and Klf4 in CRC cell lines. Furthermore, RBCK1 expression was significantly up-regulated in CRC cells cultured with conditioned medium (CM) derived from CAFs. Moreover, CAF-derived CM enhanced stemness and chemoresistance in CRC cells by over-expressing RBCK1. The in vivo experiments confirmed that RBCK1 knockdown promoted the chemotherapeutic drug sensitivity in a xenograft model. Taken together, these finding indicated that RBCK1 modulated chemosensitivity in CRC, and could be served as a promising therapeutic target for CRC prevention.

Adding Bismuth to Rabeprazole-Based First-Line Triple Therapy Does Not Improve the Eradication of Helicobacter pylori.

This randomized controlled study aimed to evaluate whether adding bismuth to the standard first-line triple therapy could improve the eradication rate of Helicobacter pylori. A total of 162 patients with Helicobacter pylori infection were randomly assigned to either the 7-day triple therapy group (RAK regimen: rabeprazole 20 mg, amoxicillin 1 g, and clarithromycin 500 mg bid; n = 81) or the bismuth plus triple therapy group (n = 81). In the RBAK group, bismuth subcitrate 360 mg twice daily was added to the RAK regimen. A follow-up endoscopy or urea breath test was performed at least 4 weeks after eradication to confirm the treatment efficacy. Comparable compliance and Helicobacter pylori eradication rates were observed in both groups in either intention-to-treat [RAK 72.8% (59/81) versus RBAK 77.8% (63/81); p = 0.47] or per protocol analysis [RAK 74.7% (59/79) versus RBAK 81.8% (63/77); p = 0.26]. Adverse effects were commonly reported (50.6% for both groups) although most of these did not cause cessation of treatment. The resistance rate was 27.2% for metronidazole and 12.3% for clarithromycin. Adding bismuth to the standard 7-day triple therapy did not substantially increase the eradication rate. Further study is needed clarifying whether extending the duration of RBAK regimen to 10-14 days can lead to a better result.

Diagnostic value of high-resolution micro-endoscopy for the classification of colon polyps.

AIM: To study a new imaging equipment, high-resolution micro-endoscopy (HRME), in the diagnosis and pathological classification of colon polyps. METHODS: We selected 114 specimens of colon polyps, 30 of which were colon polyps with known pathological types and 84 that were prospective polyp specimens; 10 normal colon mucosa specimens served as controls. We obtained images of 30 colon polyp specimens with known pathological types using HRME and analyzed the characteristics of these images to develop HRME diagnostic criteria for different pathological types of colon polyps. Based on these criteria, we performed a prospective study of 84 colon polyp specimens using HRME and compared the results with those of the pathological examination to evaluate the diagnostic value of HRME in the pathological classification of different types of colon polyps. RESULTS: In the 30 cases of known pathological type of colon polyp samples, there were 21 cases of adenomatous polyps, which comprised nine cases of tubular adenoma, seven cases of villous adenoma and five cases of mixed adenomas. The nine cases of non-adenomatous polyps included four cases of inflammatory polyps and five cases of hyperplastic polyps five. Ten cases of normal colonic mucosa were confirmed pathologically. In a prospective study of 84 cases using HRME, 23 cases were diagnosed as inflammatory polyps, 11 cases as hyperplastic polyps, 18 cases as tubular adenoma, eight cases as villous adenoma and 24 cases as mixed adenomas. After pathological examination, 24 cases were diagnosed as inflammatory polyps, 11 cases as hyperplastic polyps, 19 cases as tubular adenoma, eight cases as villous adenoma and 22 cases as mixed adenomas. Compared with the pathological examinations, the sensitivities, specificities, accuracies, and positive and negative predictive values of HRME in diagnosing inflammatory polyps (87.5%, 96.7%, 94.0%, 91.3% and 95.1%), hyperplastic polyps (72.7%, 95.9%, 92.9%, 72.7% and 95.9%), tubular adenomas (73.7%, 93.8%, 89.3%, 77.8% and 92.4%), villous adenomas (75.0%, 97.4%, 95.2%, 75.0% and 97.4%), and mixed adenomas (75.0%, 93.3%, 88.1%, 81.8% and 90.3%) were relatively high. CONCLUSION: HRME has a relatively high diagnostic value in the pathological classification of colon polyps. Thus, it may be an alternative to confocal microendoscopy in lower-resource or community-based settings.

Effects of resveratrol on the protein expression of survivin and cell apoptosis in human gastric cancer cells.

PURPOSE: This study aimed to investigate the effects of resveratrol on cell proliferation, apoptosis and protein expression of survivin in human gastric cancer (SGC7901) cell line. METHODS: SGC7901 cell proliferation and G0/G1 phase of the cell cycle induced by resveratrol (treatment group) and phosphate buffer solution (PBS) (control group) were assessed by flow cytometry. In addition, protein expression of survivin was assessed by immunohistochemistry after treatment with resveratrol. RESULTS: SGC7901 cell apoptosis rates were 0.00% and 3.45% in the control and treatment groups, respectively. Furthermore, cell cycles were significantly changed in the resveratrol group; for example, the proportion of the G0/G1 phase increased, whereas the proportion of the S and G2/M phases decreased. Survivin protein expression was significantly reduced (p<0.01) in the treatment group compared with that in the control group. CONCLUSION: Resveratrol inhibited the proliferation of SGC7901 cancer cells by inducing cell apoptosis and down-regulating survivin expression.

STAT3, p-STAT3 and HIF-1α are associated with vasculogenic mimicry and impact on survival in gastric adenocarcinoma.

Vasculogenic mimicry (VM) formation is important for invasion and metastasis of tumor cells in gastric adenocarcinoma (GAC). The present study aimed to investigate the association between signal transducer and activator of transcription-3 (STAT3), phosphor-STAT3 (p-STAT3), hypoxia-inducible factor-1α (HIF-1α) and VM formation in GAC, and discuss their clinical significance and correlation with the prognosis of patients with GAC. The expression levels of STAT3, p-STAT3, HIF-1α and VM were assessed in 60 cases of patients with GAC and 20 cases of patients with gastritis on tissue microarrays by immunohistochemical methods. The expression levels of STAT3, p-STAT3, HIF-1α and VM were higher in patients with GAC (particularly in poorly differentiated GAC) than in those with gastritis (P<0.05). The expression levels of STAT3, p-STAT3 and HIF-1α were higher in VM tissues compared with non-VM tissues (P<0.05). Positive correlations existed between STAT3, p-STAT3, HIF-1α and VM expression (P<0.05). The expression levels of STAT3, p-STAT3 and HIF-1α, VM, status of lymph node metastasis and tumor differentiation degree were associated with the overall survival time of patients with GAC (P<0.05). However, only p-STAT3 and VM expression were identified as the independent risk factors of GAC OS when analyzed with multivariate analysis. p-STAT3 and VM play a significant role in indicating the prognosis of patients with GAC. STAT3 activation may play a positive role in VM formation of GAC by the STAT3-p-STAT3-HIF-1α-VM effect axis.

[A pleiotrophin-specific siRNA and its effect on PTEN-/- MEF241 cells].

BACKGROUND & OBJECTIVE: Pleiotrophin (Ptn), a secretive growth/differentiation factor, has diverse functions involved in cell activities, including adhesion, migration, survival, growth, and differentiation. Ptn has been suggested to be a potential target for the treatment of several types of cancer. Studies have showed that rRibozyme targeting Ptn suppresses the growth, angiogenesis, and metastasis of melanoma and pancreatic cancer cells. This study was to produce a small interfering RNA (siRNA) to inhibit Ptn expression. METHODS: A group of double strand oligonucleotide fragments were synthesized and cloned into pSilencer 3.1-H1 hygro vector. siRNA-expressing vectors were transiently transfected into 3T3 cells to observe the inhibitory effects of different siRNAs on Ptn expression. Lipofectamine 2000 transfection and hygromycin B screening were used to establish PTEN-/- MEF241 cell line which could stably express silenced Ptn. The expression of Ptn was measured by Northern blot. Cell proliferation was measured. Tumorigenecity in nude mice was also measured to test if silencing the expression of Ptn can change the malignant phenotypes of PTEN-/- MEF241 cells. RESULTS: Three Ptn-specific siRNAs were designed and cloned into pSilencer 3.1-H1 hygro vector. One of them, PTEN siRNA-B, was proven to be able to effectively inhibit Ptn gene expression in PTEN-/- MEF241 cells; the inhibition rate was over 95%. The growth of PTEN-/- MEF241 cell clones was significantly slowed. Moreover, inhibiting the expression of Ptn by siRNA suppressed tumor growth and prolonged tumorigenesis duration in PTEN-/- MEF241 cell-grafted nude mice. CONCLUSION: Ptn-specific siRNA could inhibit the proliferation of PTEN-/- MEF241 cells and inhibit tumorigenesis, therefore, may be a potential target of antitumor gene therapy.