Guanylate binding protein 5 accelerates gastric cancer progression via the JAK1-STAT1/GBP5/CXCL8 positive feedback loop.

Guanylate binding protein 5 (GBP5) is a member of the interferon (IFN)-inducible large guanosine triphosphate hydrolases (GTPase) family that regulates cell-autonomous immunity and malignant tumor transformation. However, its specific roles and underlying mechanisms GBP5 in gastric cancer (GC) remain unknown. In this study, we aimed to determine the role GBP5 and underlying mechanism of GBP5 in GC cell progression. Potential oncogenic roles of GBP5 in GC as well as its relationship with the tumor immune microenvironment (TIME) were comprehensively evaluated using bioinformatics analysis. Protein expression levels of GBP5 and their correlation with clinicopathological features of patients were assessed using immunohistochemistry. In addition, diverse in vitro functional experiments were performed to identify the functions of GBP5 in GC. Downstream targets of GBP5 were identified using RNA-sequencing analysis and verified using western blotting or quantitative polymerase chain reaction analysis in different cell lines. GBP5 expression is commonly upregulated and promotes the proliferation and migration of GC cells. Mechanistically, GBP5 was regulated by the IFNγ-Janus kinase (JAK1)-signal transducer and activator of transcription 1 (STAT1) axis and induced CXCL8 expression. Interestingly, GBP5-induced CXCL8 regulated the JAK1-STAT1 signaling pathway to form a positive feedback loop. Moreover, GBP5 is closely related to the TIME and may be used as a biomarker for predicting the efficacy of immunotherapy. Our findings revealed a new JAK1-STAT1/GBP5/CXCL8 pathway and highlighted the value of GBP5 as a predictive biomarker and novel target for GC intervention.

MicroRNA-328-3p facilitates the progression of gastric cancer via KEAP1/NRF2 axis.

Gastric cancer is a common lethal malignancy and causes great cancer-related mortality worldwide. MicroRNA (miR)-328-3p is implicated in the progression of various human cancers; however, its role and mechanism in the progression of gastric cancer remain unclear.Human gastric cancer cells were incubated with miR-328-3p mimic, inhibitor or the matched negative control. Cell viability, colony formation, migrative and invasive capacity, cell apoptosis and oxidative stress were measured. To clarify the involvement of nuclear factor-E2-related factor 2 (NRF2) and kelch-like ECH-associated protein 1 (KEAP1), small interfering RNA was used. miR-328-3p was upregulated in human gastric cancer cells and tissues, and its level positively correlated with the progression of gastric cancer. miR-328-3p promoted cell viability, colony formation, migration and invasion, thereby facilitating the progression of gastric cancer. miR-328-3p mimic reduced, while miR-328-3p inhibitor increased apoptosis and oxidative stress of human gastric cancer cells. Mechanistically, miR-328-3p upregulated NRF2 via targeting KEAP1to attenuate excessive free radical production and cell apoptosis. miR-328-3p functions as an oncogenic gene and inhibiting miR-328-3p may help to develop novel therapeutic strategies of human gastric cancer.

miR-635 targets KIFC1 to inhibit the progression of gastric cancer.

Accumulating studies have shown that the dysregulation of microRNAs is related to the carcinogenesis and development of gastric cancer (GC), and the role of miR-635 in GC remains largely unknown. miR-635 and Kinesin Family Member C1 (KIFC1) mRNA expression in GC tissues and paracancerous tissues and cells were detected by quantitative real-time PCR. KIFC1 protein expression in GC tissues and paracancerous normal tissues and cells was detected by immunohistochemistry and western blot. Cell proliferation was monitored by Cell Counting Kit-8 assay and 5-bromo-2'-deoxyuridine assay. Transwell assay was employed to detect the migration and invasion of GC cells. The dual-luciferase reporter gene assay was adopted to detect the targeting relationship between miR-635 and KIFC1. Compared with paracancerous tissues, miR-635 expression was remarkably decreased in GC tissues; conversely, KIFC1 expression was significantly increased. Compared with human normal gastric epithelial cell GSE-1, miR-635 expression was markedly decreased in GC cell lines. Meanwhile, KIFC1 expression was significantly increased, and the Kaplan-Meier Plotter database showed that its high expression was remarkably associated with poor prognosis. Additionally, miR-635 can negatively regulate KIFC1. miR-635 can target KIFC1 to inhibit proliferation, migration and invasion of GC cells. Collectively, miR-635 is lowly expressed in GC, and it inhibits proliferation, migration and invasion of GC cells via regulating KIFC1.

MicroRNA-103 promotes tumor growth and metastasis in colorectal cancer by directly targeting LATS2.

Colorectal cancer (CRC) has become the third most common cancer worldwide and leads to a high mortality rate. Although colorectal cancer has been studied widely, the underlying molecular mechanism remains unclear. Increasing evidence shows that the abnormal expression of microRNAs (miRNAs) is involved in tumorigenesis. Previous studies have reported that miRNA-103 (miR-103) is dysregulated in CRC; however, the expression, function and mechanism of miR-103 in CRC are not well known. The present study showed that miR-103 was overexpressed in the primary tumor tissues of patients with CRC and was significantly associated with a more aggressive phenotype of CRC in patients. Survival rate analysis demonstrated that CRC patients with high miR-103 expression had a poorer overall survival compared with CRC patients with low miR-103 expression. In CRC cell lines, miR-103 inhibition significantly decreased the proliferation, invasion and migration of the cells in vitro. Furthermore, miR-103 repressed large tumor suppressor kinase 2 (LATS2) expression by directly binding to the LATS2-3'-untranslated region, and an inverse correlation was identified between the expression of miR-103 and LATS2 messenger RNA in primary CRC tissues. In addition, the restoration of LATS2 led to suppressed proliferation, invasion and migration of CRC cells. In vivo, miR-103 promotes tumor growth in nude mice. In summary, miR-103 performs a critical role in the promotion of the invasive and metastatic capacities of CRC, possibly by directly targeting LATS2. This miRNA may be involved in the development and progression of CRC.

Paeoniflorin inhibits human gastric carcinoma cell proliferation through up-regulation of microRNA-124 and suppression of PI3K/Akt and STAT3 signaling.

AIM: To examine the potential anti-tumor activity of paeoniflorin in the human gastric carcinoma cell line MGC-803. METHODS: Cell viability and cytotoxic effects in MGC-803 cells were analyzed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assay, respectively. Cell apoptosis of MGC-803 cells was measured using flow cytometry, DAPI staining assay and caspase-3 activity assay. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used to measure the expression of microRNA-124 (miR-124) in response to paeoniflorin. The expression of phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt), phospho-Akt (p-Akt) and phospho-signal transducer and activator of transcription 3 (p-STAT3) were also measured by quantitative RT-PCR and Western blot analysis in normal, miR-124 and anti-miR-124 over-expressing MGC-803 cells, treated with paeoniflorin. RESULTS: Paeoniflorin was found to inhibit MGC-803 cell viability in a dose-dependent manner. Paeoniflorin treatment was associated with the induction of apoptosis and caspase-3 activity in MGC-803 cells. Paeoniflorin treatment significantly increased miR-124 levels and inhibited the expression of PI3K, Akt, p-Akt and p-STAT3 in MGC-803 cells. Interestingly, the over-expression of miR-124 inhibits PI3K/Akt and phospho-STAT3 expressions in MGC-803 cells. PI3K agonist (IGF-1, 1 µg/10 µL) or over-expression of STAT3 reversed the effect of paeoniflorin on the proliferation of MGC-803 cells. Over-expression of anti-miR-124 in MGC-803 cells reversed paeoniflorin-induced up-regulation. CONCLUSION: In summary, the in vitro data suggest that paeoniflorin is a potential novel therapeutic agent against gastric carcinoma, which inhibits cell viability and induces apoptosis through the up-regulation of miR-124 and suppression of PI3K/Akt and STAT3 signaling.

miR-132 inhibits colorectal cancer invasion and metastasis via directly targeting ZEB2.

AIM: To investigate the biological role and underlying mechanism of miR-132 in colorectal cancer (CRC) progression and invasion. METHODS: Quantitative RT-PCR analysis was used to examine the expression levels of miR-132 in five CRC cell lines (SW480, SW620, HCT116, HT29 and LoVo) and a normal colonic cell line NCM460, as well as in tumor tissues with or without metastases. The Kaplan-Meier method was used to analyze the prognostic significance of miR-132 in CRC patients. The biological effects of miR-132 were assessed in CRC cell lines using the transwell assay. Quantitative RT-PCR and western blot analyses were employed to evaluate the expression of miR-132 targets. The regulation of ZEB2 by miR-132 was confirmed using the luciferase activity assay. RESULTS: miR-132 was significantly down-regulated in the CRC cell lines compared with the normal colonic cell line (P < 0.05), as well as in the CRC tissues with distant metastases compared with the tissues without metastases (10.52 ± 4.69 vs 23.11 ± 7.84) (P < 0.001). Down-regulation of miR-132 was associated with tumor size (P = 0.016), distant metastasis (P = 0.002), and TNM stage (P = 0.020) in CRC patients. Kaplan-Meier survival curve analysis indicated that patients with low expression of miR-132 tended to have worse disease-free survival than patients with high expression of miR-132 (P < 0.001). Moreover, ectopic expression of miR-132 markedly inhibited cell invasion (P < 0.05) and the epithelial-mesenchymal transition (EMT) in CRC cell lines. Further investigation revealed ZEB2, an EMT regulator, was a downstream target of miR-132. CONCLUSION: Our study indicated that miR-132 plays an important role in the invasion and metastasis of CRC.

[Value of normalization window of tumor vasculature in neoadjuvant chemotherapy for patients with unresectable gastric cancer].

OBJECTIVE: To evaluate the value of normalization window of tumor vasculature (NWTV) in patients with unresectable gastric cancer undergoing neoadjuvant chemotherapy. METHODS: From October 2010 to March 2011, 93 patients with unresectable advanced or locally advanced gastric carcinoma were prospectively collected and randomly divided to Group A(n=30), Group B(n=29), and Group C(n=34). Group A received FOLFOX4 as conventional neoadjuvant chemotherapy. Group B received FOLFOX4 plus bevacizumab. The treatment was adjusted in Group C according to the hypothesis of NWTV with neoadjuvant chemotherapy delivered 5 days after bevacizumab treatment. The efficacy, drug toxicity and clinical outcome were assessed and compared between the three groups. RESULTS: There were no significant differences among the 3 groups in demographics(P>0.05). All the patients completed the neoadjuvant chemotherapy. Efficacy and toxicity between the three groups were comparable(P>0.05). The rates of tumor downstaging in the three groups were 56.7%(17/30), 72.4%(21/29), 85.3%(29/34), respectively, with a significantly lower downstaging rate in Group C as compared to Group A(P<0.05). R0 resection rates were 23.3%(7/30), 27.6%(8/29), 52.9% (18/34), respectively, with significantly higher R0 resection rate in Group C as compared to Group A and Group B(All P<0.05). There was no perioperative death in this cohort. Postoperative complications were comparable among the 3 groups(P>0.05). CONCLUSIONS: Anti-angiogenesis agent can improve the efficacy of neoadjuvant chemotherapy in unresectable gastric cancer. Furthermore, administration according to NWTV may achieve better outcomes.