Renhua Guo

Critical role of aquaporin-3 in the human epidermal growth factor-induced migration and proliferation in the human gastric adenocarcinoma cells.

Background: Aquaporins (AQPs) are expressed in many different tumor cell types in human. New evidence for the involvement of AQPs in cell migration and proliferation adds AQPs to an expanding list of effectors in tumor biology. Aims: The aim of this study was to investigate whether AQP3 expression in the human gastric carcinoma cell lines, AGS and SGC7901, enhances cell migration and proliferation. Methods: Cultured AGS or SGC7901 cells were treated with human epidermal growth factor (hEGF) and subjected to cell migration assay and cell proliferation assay. The expression or activation level of proteins was analyzed by western blot. AQP3 knockdown was obtained by small interfering (si) RNA. Results: Here, we showed that AQP3 is expressed in the human gastric cancer cell lines, AGS and SGC7901. The hEGF induced AQP3 expression in a time- and dose-dependent manner and increased gastric cancer cell migration and proliferation. AQP3 knockdown by siRNA inhibited hEGF-induced AQP3 expression and thus cell migration and proliferation. Furthermore, a mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) inhibitor U0126 inhibited hEGF-induced AQP3 expression and cell migration or proliferation. Conclusions: Collectively, our findings provide for the first time that AQP3 plays a critical role in hEGF-induced cancer cell migration and proliferation and that hEGF induces AQP3 expression via ERK signal transduction pathways. These finds provide evidence for a novel role of AQP3 in human gastric carcinoma as a potentially important determinant of tumor growth and spread.

Expression profile of multiple aquaporins in human gastric carcinoma and its clinical significance.

BACKGROUND New evidence for involvement of aquaporins (AQPs) in cell migration and proliferation adds AQPs to an expanding list of effectors in tumor biology. But there is few report concerning the expression and role of AQPs in human gastric carcinogenesis so far. The aim of this current study was to investigate the expression profile of AQPs in human gastric carcinoma and its significance. METHODS We screened the expression profile of AQP0 approximately AQP12 in gastric adenocarcinoma tissues and corresponding normal mucosa from 89 patients with gastric cancer by reverse transcriptase polymerase chain reaction (RT-PCR), Western blot analysis and immunochemical assay. The relationship between AQPs expression and clinicopathologic characteristics of patients was evaluated. RESULTS Based on RT-PCR of 13 AQPs examined, AQP1, 3, 4, 5 and 11 were expressed in human gastric cancers or normal gastric tissues, and AQP3, 4 and 5 exhibited differential expression between human gastric carcinomas and corresponding normal tissues, which was confirmed by Western blot analyses. Immunohistochemical assay showed that AQP4 protein was expressed mainly in the membrane of parietal cell and chief cell in the normal gastric mucosa, and absent in carcinoma tissues. AQP3 and AQP5 were detected remarkably stronger in the carcinoma tissues than that in normal mucosa by immunofluorescence. AQP3 expression in cases with undifferentiated tumor was more than that in cases with well-differentiated tumor. Both AQP3 and AQP5 expression were associated with lymph node metastasis and lymphovascular invasion in patients. CONCLUSIONS These findings of differential expressions of AQPs and their correlation with clinicopathologic characteristics implicated AQPs might play a role in human gastric carcinogenesis.

Gefitinib or Erlotinib as Maintenance Therapy in Patients with Advanced Stage Non-Small Cell Lung Cancer: A Systematic Review

Background Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI), gefitinib and erlotinib have been tested as maintenance therapy in patients with advanced non-small-cell lung cancer (NSCLC). The studies are quite heterogenous regarding study size and populations, and a synopsis of these data could give some more insight in the role of maintenance therapy with TKI. Methods In September 2012 we performed a search in the pubmed, EMBASE and Cochrane library databases for randomized phase III trials exploring the role of gefitinib or erlotinib in advanced non-small cell lung cancer. Through a rigorous selection process with specific criteria, five trials (n = 2436 patients) were included for analysis. Standard statistical methods for meta-analysis were applied. Results TKIs (gefitinib and erlotinib) significantly increased progression-free survival (PFS) [hazard ratio (HR) 0.63, 95% confidence interval (CI) 0.50–0.76, I2 = 78.1%] and overall survival (HR 0.84, 95% CI 0.76–0.93, I2 = 0.0%) compared with placebo or observation. The PFS benefit was consistent in all subgroups including stage, sex, ethnicity, performance status, smoking status, histology, EGFR mutation status, and previous response to chemotherapy. Patients with clinical features such as female, never smoker, adenocarcinoma, Asian ethnicity and EGFR mutation positive had more pronounced PFS benefit. Overall survival benefit was observed in patients with clinical features such as female, non-smoker, smoker, adenocarcinoma, and previous stable to induction chemotherapy. Severe adverse events were not frequent. Main limitations of this analysis are that it is not based on individual patient data, and not all studies provided detailed subgroups analysis. Conclusions The results show that maintenance therapy with erlotinib or gefitinib produces a significant PFS and OS benefit for unselected patients with advanced NSCLC compared with placebo or observation. Given the less toxicity of TKIs than chemotherapy and simple oral administration, this treatment strategy seems to be of important clinical value.

c-Met upregulates aquaporin 3 expression in human gastric carcinoma cells via the ERK signalling pathway

Aquaporin 3 (AQP3) and c-Met are both overexpressed in human gastric carcinoma and highly associated with its metastasis and invasion. However, it still remains unknown whether c-Met and AQP3 correlate with each other. Herein, we demonstrated that c-Met expression in gastric cancer tissues significantly correlated with differentiation, lymph node metastasis and lymphovascular invasion, and c-Met exhibited marked association with AQP3 expression. Immunoblotting assays showed that hHGF phosphorylated c-Met in SGC7901 and AGS cells and upregulated AQP3 expression in a dose- or time-dependent way. RNAi against c-Met reduced total c-Met levels by about two thirds in both AGS and SGC7901 cells and attenuated hHGF-induced AQP3 expression significantly. In vitro migration and proliferation assays showed that siRNA against AQP3 noticeably restrained HGF-promoted migration and proliferation of these cells. Furthermore, Immunoblotting studies revealed that HGF induced phosphorylation of ERK, and pre-treatment with U0126, a MAPK/ERK inhibitor, partially inhibited hHGF-induced increase in AQP3 expression. Together, these data provide initial evidence that c-Met regulates the expression of AQP3 via the ERK signalling pathway in gastric carcinoma. These findings assist in understanding the mechanism of growth and invasion of gastric carcinoma, and provide a possible strategy for the inhibition of gastric tumor metastasis.

MiR-1 targets PIK3CA and inhibits tumorigenic properties of A549 cells.

MicroRNAs are small endogenous RNAs that play important roles in the pathogenesis of human diseases, including malignancy. MicroRNA-1 (miR-1) is downregulated in non-small cell lung cancer (NSCLC); however, the underlying mechanisms by which it suppresses tumorigenesis in NSCLC are largely unknown. We investigated whether phosphoinositide-3-kinase catalytic subunit alpha (PIK3CA) was a novel target of miR-1 in the NSCLC cell line A549, and the mechanism of miR-1 inhibition of the tumorigenic properties of A549 cells is discussed. The influence of miR-1 on A549 cells was studied by transfection with miR-1 mimics or inhibitor. MiR-1 overexpression led to downregulation of PIK3CA protein, but not mRNA by western blot and quantitative real-time PCR, respectively. The dual-luciferase reporter assay confirmed that miR-1 targeted PIK3CA directly. PIK3CA downregulation by miR-1 mimics led to a significant reduction of phosphorylated Akt and survivin protein, the downstream targets of the PI3K/Akt pathway. Cell proliferation was studied using a cell counting kit. Migration and invasion were evaluated by Transwell and Matrigel assays, respectively. Cell cycle and apoptosis were detected by flow cytometry. The results were that miR-1 upregulation inhibited A549 cell proliferation, migration, and invasion. These findings indicate that miR-1 may play an important role in the pathogenesis of NSCLC by regulating PIK3CA through the PI3K/Akt pathway. Increasing miR-1 expression may provide a novel approach for NSCLC treatment.

A six-microRNA panel in plasma was identified as a potential biomarker for lung adenocarcinoma diagnosis

Differently expressed microRNAs (miRNAs) in the plasma of lung adenocarcinoma (LA) patients might serve as biomarkers for LA detection. MiRNA expression profiling was performed using Exiqon panels followed by the verification (30 LA VS. 10 healthy controls (HCs)) with quantitative reverse transcription polymerase chain reaction (qRT-PCR) in the screening phase. Identified miRNAs were confirmed through training (42 LA VS. 32 HCs) and testing stages (66 LA VS. 62 HCs) by using qRT-PCR based absolute quantification methods. A total of six up-regulated plasma miRNAs (miR-19b-3p, miR-21-5p, miR-221-3p, miR-409-3p, miR-425-5p and miR-584-5p) were identified. The six-miRNA panel could discriminate LA patients from HCs with areas under the receiver operating characteristic curve of 0.72, 0.74 and 0.84 for the training, testing and the external validation stage (33 LA VS. 30 HCs), respectively. All the miRNAs identified except miR-584-5p were significantly up-regulated in LA tissues. MiR-19-3p, miR-21-5p, miR-409-3p and miR-425-5p showed high expression in arterial plasma with borderline significance. Additionally, miR-19-3p, miR-21-5p and miR-221-3p were significantly up-regulated in exosomes extracted from LA peripheral plasma samples. In conclusion, we identified a six-miRNA panel in peripheral plasma which might give assistance to the detection of LA at least for Asian population to a certain extent.

Correlation between the expression levels of miR-1 and PIK3CA in non-small- cell lung cancer and their relationship with clinical characteristics and prognosis

AIMS To examine the relationship between the expression levels of miR-1 and PIK3CA in resected non-small-cell lung cancer (NSCLC) tissues and clinical characteristics and prognosis. MATERIALS & METHODS Levels of miR-1 and PIK3CA in cancerous and normal tissues obtained from 55 patients with NSCLC were measured by real-time PCR and western blot assays, and their associations with clinicopathological features were evaluated. RESULTS A total of 69.1% of the NSCLC tissue samples showed low miR-1 expression (p < 0.05) and 70.9% showed high PIK3CA expression (p < 0.05). Patients with low miR-1 expression and those with high PIK3CA expression had significantly higher incidences of lymph node metastases and postoperative recurrences within 1 year after surgery than those with moderate miR-1 expression and moderate PIK3CA expression (p < 0.05 for both). CONCLUSION Low expression of miR-1 and overexpression of PIK3CA in NSCLC tissues may be useful predictors of lymph node metastasis and postoperative recurrence in patients with NSCLC.

Subsequent chemotherapy reverses acquired tyrosine kinase inhibitor resistance and restores response to tyrosine kinase inhibitor in advanced non-small-cell lung cancer

BackgroundPatients with advanced or metastatic non-small cell lung cancer (NSCLC) can develop acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors (TKIs) erlotinib and gefitinib. Here, we report the successful treatment with alternating chemotherapy and TKIs of two cases of advanced NSCLC who developed resistance to TKI.Case presentationTwo patients with advanced or metastatic NSCLC were treated with palliative chemotherapy followed by erlotinib/gefitinib. When TKI therapy failed, two cycles of chemotherapy were provided, which were followed by re-challenge with erlotinib or gefitinib.ConclusionNSCLC patients with acquired TKI resistance should be managed aggressively whenever possible. Subsequent chemotherapy and target treatment is one of the reasonable choices for those with an initial dramatic clinical response with erlotinib/gefitinib treatment. Further studies are warranted to substantiate the association of erlotinib /gefitinib treatment with the efficacy of NSCLC patients with acquired TKI failure.

Combine therapy of gefitinib and fulvestrant enhances antitumor effects on NSCLC cell lines with acquired resistance to gefitinib

Gefitinib, an EGFR receptor tyrosine kinase inhibitor, is approved for clinical use in the treatment of non-small cell lung cancer (NSCLC), but the emergence of mutations resistant to these inhibitors, such as T790M, has become a clinical problem. According to statistics, female patients, the presence of adenocarcinoma or non-smokers experienced a higher response rate. This may be involved in interaction between the estrogen receptor (ER) and the epidermal growth factor receptor (EGFR). To test whether inhibition of the ER signaling pathway affects the antitumor effect of gefitinib, gefitinib and an ER antagonist, fulvestrant, were administered to NSCLC cell lines with acquired resistance to gefitinib. Compared with treatment of either fulvestrant or gefitinib alone, drug combination obviously decreased proliferation of H1976, H1650 and PC-9 cells coming from adenocarcinoma. Rapid activations of EGFR pathway by E2β were observed in H1975 cells with T790M mutation. Additionally, EGFR and ERs expression were down-regulated respectively in response to estrogen and EGF but up-regulated in response to fulvestrant and gefitinib in vitro. These results suggest that there is a functional cross-signaling between the EGFR/ER pathways in NSCLC with acquired resistance to gefitinib, possibly providing rationale for combining gefitinib with anti-estrogen therapy for advanced NSCLC treatment.

Autologous cytokine-induced killer cell therapy in lung cancer patients: A retrospective study

Cytokine-induced killer (CIK) cells have the ability to kill tumor cells in vitro and in vivo. This study aimed to evaluate the clinical effect of adjuvant immunotherapy with CIK cells on the prognosis of lung cancer patients. In the present study, we investigated the clinical outcomes of autologous CIK cell immunotherapy for patients with lung cancer in a case-control study. Our study included 60 patients who received chemotherapy combined with autologous CIK cell adoptive immunotherapy in CIK treatment group and 60 patients who received chemotherapy alone in the control group. Progression-free survival (PFS) and overall survival (OS) of these two groups were evaluated. After 14 days of incubation in vitro, the percentages of CD3(+), CD3(+)CD8(+), CD3(+)CD56(+) and CD3(-)CD56(+) were significantly increased (P<0.05). The clinical symptoms of 60 patients were apparently improved. No severe toxicity and side effects were observed in the CIK treatment group. The 3-year, 5-year PFS rates were 44.7% and 26.8% and the 3-year, 5-year OS rates were 74% and 62% in the CIK group, respectively, which were significantly improved compared to that in the control group. The median PFS and OS in the CIK group were significantly improved than those in the control group (PFS, 24 months vs. 14 months, P=0.014; OS, 72 months vs. 44 months, P=0.006). Our results indicated that autologous CIK cells can efficiently improve the immunological status and prolong PFS and OS in patients with lung cancer.