Jianping Xiong

Targeting miR-21 enhances the sensitivity of human colon cancer HT-29 cells to chemoradiotherapy in vitro.

5-Fluorouracil (5-FU) is a classic chemotherapeutic drug that has been widely used for colorectal cancer treatment, but colorectal cancer cells are often resistant to primary or acquired 5-FU therapy. Several studies have shown that miR-21 is significantly elevated in colorectal cancer. This suggests that this miRNA might play a role in this resistance. In this study, we investigated this possibility and the possible mechanism underlying this role. We showed that forced expression of miR-21 significantly inhibited apoptosis, enhanced cell proliferation, invasion, and colony formation ability, promoted G1/S cell cycle transition and increased the resistance of tumor cells to 5-FU and X radiation in HT-29 colon cancer cells. Furthermore, knockdown of miR-21 reversed these effects on HT-29 cells and increased the sensitivity of HT-29/5-FU to 5-FU chemotherapy. Finally, we showed that miR-21 targeted the human mutS homolog2 (hMSH2), and indirectly regulated the expression of thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD). These results demonstrate that miR-21 may play an important role in the 5-FU resistance of colon cancer cells.

miR-320 enhances the sensitivity of human colon cancer cells to chemoradiotherapy in vitro by targeting FOXM1

miR-320 expression level is found to be down-regulated in human colon cancer. To date, however, its underlying mechanisms in the chemo-resistance remain largely unknown. In this study, we demonstrated that ectopic expression of miR-320 led to inhibit HCT-116 cell proliferation, invasion and hypersensitivity to 5-Fu and Oxaliplatin. Also, knockdown of miR-320 reversed these effects in HT-29 cells. Furthermore, we identified an oncogene, FOXM1, as a direct target of miR-320. In addition, miR-320 could inactive the activity of Wnt/β-catenin pathway. Finally, we found that miR-320 and FOXM1 protein had a negative correlation in colon cancer tissues and adjacent normal tissues. These findings implied that miR-320-FOXM1 axis may overcome chemo-resistance of colon cancer cells and provide a new therapeutic target for the treatment of colon cancer.

MiR-1271 Inhibits Cell Proliferation, Invasion and EMT in Gastric Cancer by Targeting FOXQ1.

Background/Aims: FOXQ1 overexpression has been reported to enhance tumor growth and invasion. However, the biological function of FOXQ1 and the mechanism underlying its upregulation in gastric cancer (GC) remain unknown. Methods: QPCR was used to detect the expression of miR-1271 and FOXQ1 in specimens from GC patients. FOXQ1-siRNA, and miR-1271 mimics and inhibitor were transfected into human MGC-803 and SGC-7901 cells. The transwell assay was used to examine the cell invasive ability. The regulation mechanism was confirmed by luciferase reporter assay. Markers of epithelial-mesenchymal transition (EMT) were detected by western blot analysis. Results: MiR-1271 was downregulated in both GC tissues and GC cell lines. The expression of miR-1271 was inversely correlated with tumor size (P = 0.017), tumor stage (P = 0.035), lymph node metastasis (P = 0.018), and TNM stage (P = 0.025). Ectopic expression of miR-1271 dramatically suppressed GC cell proliferation, invasion, and EMT. Furthermore, FOXQ1 was identified as a direct target of miR-1271. Knockdown of FOXQ1 inhibited GC cell malignant behavior, whereas FOXQ1 overexpression partially restored the suppression effects of miR-1271. Additionally, miR-1271 expression was negatively correlated with FOXQ1 in GC tissues. Conclusions: MiR-1271 inhibits cell proliferation, invasion, and EMT in GC by directly suppressing FOXQ1 expression.

MicroRNA-506 inhibits gastric cancer proliferation and invasion by directly targeting Yap1

Increasing evidence indicates that microRNA (miR)-506 plays a vital role in tumorigenesis; however, the role of miR-506 in gastric cancer (GC) is unclear and needs further investigation. In the present study, we showed that the decrease in the expression of miR-506 is associated with tumor size, pathological tumor node metastasis (TNM) stage, and lymph node metastasis in 63 GC patient tumors. We found that patients with lower expression of miR-506 had a poor prognosis than that with the patients with high expression of miR-506. Notably, the ectopic expression of miR-506 was sufficient to inhibit cell proliferation, invasion, and epithelial-mesenchymal transition in the GC cells. Moreover, results from luciferase reporter assays identified miR-506 as a direct regulator of Yes-associated protein 1 (Yap1). Reintroduction of Yap1 rescues miR-506-induced effects on SGC-7901 cell proliferation and invasion. This function of miR-506/Yap1 axis is clinically significant, as the level of miR-506 is inversely correlated with Yap1 mRNA expression in matched tissues. Thus, our study demonstrates that miR-506 may act as a tumor suppressor in GC and that the miR-506/Yap1 axis may help us better understand the molecular mechanisms of GC progression.

Interference with the β-catenin gene in gastric cancer induces changes to the miRNA expression profile

Aberrant activation of the Wnt/β-catenin signaling pathway plays a major role in carcinogenesis and the progression of many malignant tumors, especially gastric cancer (GC). Some research has suggested that expression of the β-catenin protein is associated with clinicopathologic factors and affects the biological behaviors of GC cells. However, the mechanism of these effects is not yet clear. Studies show that the Wnt/β-catenin pathway regulates some miRNAs. We hypothesize that oncogenic activation of β-catenin signaling is involved in the formation of GC through regulating certain microRNAs (miRNAs). The results of the current study demonstrate that expression of the β-catenin protein is associated with many clinicopathologic characteristics including the degree of differentiation, depth of tumor invasion, tumor site, and 5-year survival rate. We found that silencing the expression of β-catenin with lentiviruses could delay cell proliferation, promote apoptosis, weaken the invasive power of GC cells, and increase the sensitivity of GC cells to 5-fluorouracil in vitro. Using miRNA microarrays to detect changes in the miRNA transcriptome following interference with β-catenin in GC cells, we found that miR-1234-3p, miR-135b-5p, miR-210, and miR-4739 were commonly upregulated and that miR-20a-3p, miR-23b-5p, miR-335-3p, miR-423-5p, and miR-455-3p were commonly downregulated. These data provide a theoretical basis for the potential interaction between miRNA and the β-catenin signaling pathway in GC.

MiR-93-5p promotes gastric cancer-cell progression via inactivation of the Hippo signaling pathway

MiR-93-5p has been previously found to be associated with gastric cancer (GC) tumorigenesis; however, the current understanding of its function in this context remains largely incomplete. In the present study, we showed that miR-93-5p was upregulated in GC tissues. We also demonstrated that miR-93-5p overexpression promoted the proliferation, migration, invasion, and chemoresistance of SGC-7901 cells in vitro, and conversely, that endogenously silencing miR-93-5p expression induced the opposite effects in HGC-27 cells. Overexpression of miR-93-5p was found to inactivate the Hippo pathway, and furthermore, miR-93-5p knockdown activated Hippo signaling. MiR-93-5p upregulation was also shown to inhibit the expression of two well-characterized Hippo pathway regulators, protocadherin Fat 4 (FAT4), and large tumor suppressors 2 (LATS2), at both the mRNA and protein level. Additionally, the results of bioinformatics analyses and luciferase reporter assays indicated that miR-93-5p directly targets the 3-UTR of FAT4 and LATS2. Taken together, these results demonstrate that miR-93-5p promotes GC-cell progression via the inactivation of the Hippo signaling pathway, and thus, represents a potential therapeutic target for the treatment of GC.

YAP1 inhibits circRNA-000425 expression and thus promotes oncogenic activities of miR-17 and miR-106

YAP1, a vital effector of Hippo pathway, promotes cancer development via transcriptionally regulating a batch of target genes involved in various signaling pathways, including proliferation, apoptosis, and cell drug sensitivity. Recently, circular RNAs (circRNAs) have been shown to control gene expression post-transcriptionally and become a new layer of gene regulation. However, whether circRNAs play roles in YAP1-induced tumorigenesis is still largely elusive. Here, we identify circRNA-000425 as a new inhibitory target of YAP1, and also find that it binds to miR-17/miR-106b, and thus suppresses cancer cell growth induced by these miRNAs. circRNA-000425 is revealed as a YAP1 target through circRNA microarray analysis of RNAs extracted from cells treated with or without YAP1 siRNAs, and further confirmed by RT-q-PCR and ChIP assays. Interestingly, bioinformatics analysis, luciferase assay, and RT-q-PCR results showed that circRNA-000425 binds to miR-17 and miR-106b, but not let-7a, and rescues the inhibitory effect of miR-17/miR-106 on the expressions of both p21 and BIM. In addition, colony formation and MTT assay showed that circRNA-000425 inhibits cancer cell growth induced by miR-17. These findings reveal a mechanism by which YAP1 promotes oncogenic activities of miR-17 and miR-106b through transcriptionally inhibiting circRNA-000425 expression.

TRIM24 promotes the aggression of gastric cancer via the Wnt/β‑catenin signaling pathway

Tripartite motif-containing 24 (TRIM24) is important in tumor development and progression. However, the role of TRIM24 in gastric cancer (GC) and the mechanisms underlying the dysregulated expression of TRIM24 remain to be fully elucidated. In the present study, it was found that TRIM24 was frequently overexpressed in GC cell lines and tissues compared with normal controls, as determined by western blotting and immunohistochemical staining. The high nuclear expression of TRIM24 was correlated with the depth of invasion (P=0.007), tumor-node-metastasis stage (P=0.005), and lymph node metastasis (P=0.027), and shorter overall survival rates (P=0.010) in patients with GC. Small interfering RNA-mediated knockdown of TRIM24 inhibited cell proliferation, colony formation, migration, invasion and the nuclear accumulation of β-catenin, and it delayed cell cycle progression and induced apoptosis. In addition, the expression of TRIM24 was positively correlated with that of β-catenin in GC tissues. TRIM24 knockdown decreased the expression of Wnt/β-catenin target genes, whereas the activation of Wnt/β-catenin signaling by lithium chloride reversed the effects of TRIM24 knockdown. Taken together, these data suggested that TRIM24 was a prognostic or potential therapeutic target for patients with GC and was important in the activation of the Wnt/β-catenin pathway during the progression of GC.

Regulation of TRIM24 by miR-511 modulates cell proliferation in gastric cancer.

BackgroundIncreasing evidence highlights the important roles of tripartite motif containing 24 (TRIM24) in tumor initiation and malignant progression in many tumors, including gastric cancer (GC). Although TRIM24 expression is remarkably upregulated during GC carcinogenesis, the molecular mechanisms underlying TRIM24 dysregulation remain unexplored.MethodsIn this study, miRNA target prediction tools were applied to explore miRNAs that potentially target TRIM24. Western blot and quantitative reverse-transcriptase PCR (qRT-PCR) were performed to detected TRIM24 and miR-511 expression in GC tissues and cell lines. Dual-luciferase reporter assay was utilized to validate if TRIM24 is a direct target gene of miR-511. CCK-8 assay, cell colony formation assay, EdU incorporation assay and cell cycle analysis were performed to determine whether miR-511-mediated regulation of TRIM24 could affect GC progression.ResultsIn our study, miR-511 was found to be downregulated in GC and an inverse correlation was observed between TRIM24 and miR-511 expression in primary GC tissues and cell lines. Dual-luciferase reporter assay further verified TRIM24 is a direct target of miR-511. Functional assays showed miR-511 overexpression inhibited cell growth, colony formation ability and cell cycle progression. Conversely, inhibition of endogenous miR-511 promoted these phenotypes in GC cells. Moreover, reintroduction of TRIM24 rescued miR-511-induced inhibitory effects on GC cells. Furthermore, miR-511 elicits tumor-suppressive effects through inactivating PI3K/AKT and Wnt/β-catenin pathways by suppressing TRIM24.ConclusionsOur results provide the new evidence supporting the tumor-suppressive role of miR-511 in GC by suppressing TRIM24, suggesting that this novel miR-511/TRIM24 axis is critical in the control of gastric cancer tumorigenesis.

A study of weekly docetaxel and carboplatin as first-line chemotherapy for advanced non-small cell lung cancer

BACKGROUNDnWeekly docetaxel demonstrated similar efficacy but better tolerability than standard triweekly docetaxel, and carboplatin was less nephrotoxic, neurotoxic and emetogenic than cisplatin. This study aimed to evaluate the efficacy and safety of weekly docetaxel with carboplatin as first-line chemotherapy for advanced non-small cell lung cancer (NSCLC).nnnMETHODSnForty-three Chinese patients have been included. Patients were administered docetaxel at a dose of 35 mg/m(2) on days 1, 8, 15 and carboplatin at an area under the curve (AUC) 5 on day 1 every 28-day cycle (maximum six cycles).nnnRESULTSnOf the 43 eligible patients, the assessed overall response rate (RR) was 30.2% with 30.2% partial response (PR) in 13 patients, 48.8% stable disease (SD) in 21 patients and 20.9% progressive disease (PD) in 9 patients. The estimated median progression free survival and median overall survival (OS) time were respectively, 120 days (95% CI: 80-160 days) and 340 days (95% CI: 224-456 days) with the patients surviving of 46.5% (95% CI: 31.6-61.4%) at one year and 20.0% (95% CI: 7.1-33.3%) at two years. The major grade 3/4 hematological toxicities were included leucocytopenia in 6 patients (13.9%) and neutropenia in 8 patients (18.6%). One patient (2.3%) suffered grade 1 febrile neutropenia. All grade of the nonhematological toxicities, such as nausea, vomiting, alopecia and fatigue held the proportion of 48.8% (grade 3/4 4.6%), 27.9%, 55.8% and 53.5% (grade 3/4 9.3%), respectively.nnnCONCLUSIONSnThe combination of weekly docetaxel and carboplatin showed feasible efficacy with acceptable hematologic toxicities for advanced lung cancer.