Copy number variations of neurotrophic tyrosine receptor kinase 3 (NTRK3) may predict prognosis of ovarian cancer.

Platinum resistance is a critical barrier for clinicians to improve the survival of ovarian cancer. Our study evaluated the correlation between copy number variations (CNVs) of neurotrophic tyrosine receptor kinase 3 (NTRK3) and the prognosis of ovarian cancer, which might predict platinum resistance in ovarian cancer patients.Array comparative genomic hybridization (CGH) was used to test gene backgrounds between platinum-sensitive and platinum-resistant relapsed populations and CNVs of NTRK3 were indicated by cluster analysis. Fluorescence in situ hybridization (FISH) was adopted in 41 cases for further verification, which confirmed the results of array CGH. Spearman's rank correlation analysis and χ test were used to evaluate the accuracy of CNVs of NTRK3 which predicted platinum-sensitive or platinum-resistant recurrence.We detected CNVs of NTRK3 between 2 groups by array CGH, and amplification of NTRK3 was confirmed by FISH in the platinum-sensitive recurrence group with enlarged samples. The test concordance of 2 methods was 78.6%. Among 41 cases with satisfied FISH results, the median time to recurrence (TTR) of patients with amplified and nonamplified NTRK3 were respectively 18 and 5 months (P <.01). The cut-off value of TTR to differentiate platinum-sensitive or platinum-resistant recurrence was 6 months in accordance with clinical practice. According to the above standard, 15 cases with NTRK3 amplification were platinum-sensitive and 12 cases without NTRK3 amplification were platinum-resistant recurrences which demonstrated that the accuracy of NTRK3 amplification/nonamplification to predict recurrent types was 65.9% (27/41).CNVs of NTRK3 were associated with platinum-sensitive and platinum-resistant recurrences. Amplification of NTRK3 perfectly predicted platinum-sensitive relapse of ovarian cancer.

MicroRNA-mRNA functional pairs for cisplatin resistance in ovarian cancer cells.

Ovarian cancer is the leading cause of death in women worldwide. Cisplatin is the core of first-line chemotherapy for patients with advanced ovarian cancer. Many patients eventually become resistant to cisplatin, diminishing its therapeutic effect. MicroRNAs (miRNAs) have critical functions in diverse biological processes. Using miRNA profiling and polymerase chain reaction validation, we identified a panel of differentially expressed miRNAs and their potential targets in cisplatin-resistant SKOV3/DDP ovarian cancer cells relative to cisplatin-sensitive SKOV3 parental cells. More specifically, our results revealed significant changes in the expression of 13 of 663 miRNAs analyzed, including 11 that were up-regulated and 2 that were down-regulated in SKOV3/DDP cells with or without cisplatin treatment compared with SKOV3 cells with or without cisplatin treatment. miRNA array and mRNA array data were further analyzed using Ingenuity Pathway Analysis software. Bioinformatics analysis suggests that the genes ANKRD17, SMC1A, SUMO1, GTF2H1, and TP73, which are involved in DNA damage signaling pathways, are potential targets of miRNAs in promoting cisplatin resistance. This study highlights candidate miRNA-mRNA interactions that may contribute to cisplatin resistance in ovarian cancer.

[MiR-17-92 in cancer].

MicroRNAs (miRNAs) are a class of short regulatory non-coding RNAs (22-24 nt) widely expressed in living organisms. Shortly after their discovery, microRNAs are found to participate in the development of a variety of diseases. miR-17-92 and its paralog are one of them, recent studies have revealed their critical roles not only in the development of lung, heart, immune system but also in carcinogenesis. The present article mainly focuses on their different expression patterns and molecular mechanisms to elucidate their contribution to cancer development.

[Effects of survivin siRNA on growth, apoptosis and chemosensitivity of ovarian cancer cells SKOV3/DDP].

OBJECTIVE: To explore a new approach in gene therapy of ovarian cancer, we used RNAi to inhibit survivin gene expression, and explore the effect of survivin and neu RNAi on growth, apoptosis and chemosensitivity of ovarian cancer cell line SKOV3/DDP cells. METHODS: Expression vector of survivin gene-targeting siRNA was constructed using pSilencer 1.0-U6 vector containing U6 promotor (pSilencer-survivin) and transfected into SKOV3/DDP cells by lipofectamine. The untransfected group and pSilencer-control group were used as control. The expressions of survivin mRNA and protein were identified by RT-PCR and Western blot assay. The proliferation of SKOV3/DDP cells was determined by MTT assay. The apoptosis rate and cell cycle distribution were analyzed by flow cytometry. Cisplatin (DDP) resistance experiment was performed in SKOV3/DDP cells with RNAi. RESULTS: Survivin RNAi plasmid knocked-down survivin expression in SKOV3/DDP cells obviously, arrested the cells at G(1)/G(0) phase, inhibited the cell proliferation and promoted cell apoptosis. The IC(50) of DDP to SKOV3/DDP cells transfected with survivin siRNA was dropped. CONCLUSION: Survivin RNAi can partly suppress the expression of survivin in SKOV3/DDP cells, inhibit the cell proliferation and promote cell apoptosis. Survivin RNAi can enhance the cell sensitivity to apoptosis induced by cisplatin, which implies that survivin RNAi may partly reverse the drug resistance of ovarian cancer. RNAi could be a new approach for gene therapy of cancer.

[Current advances in the mechanic studies of human papillomavirus-induced oncogenesis].

Human papillomavirus (HPV) is a common small DNA tumor virus that specifically infects squamous epithelial cells and causes benign or malignant epithelial lesions such as genital warts and cervical cancer. High-risk HPV is detected in specimens of more than 90% of cervical cancer. In the 7. 9 kb genome of HPV, E6 and E7 are the crucial viral oncoproteins that consistently maintained after viral integration into host cell genome. These two proteins interfere with cell proliferation and differentiation through interacting with important tumor suppressors including p53 and pRb. High-risk HPV E6/E7 also induces genomic instability, facilitating cell transformation.

Amplification and overexpression of Aurora-A in esophageal squamous cell carcinoma.

Aurora-A/BTAK/STK15 gene which encodes a centrosome-associated kinase is located on chromosome 20q13.2, a highly amplified region in various human tumors. Recent studies have demonstrated the overexpression and amplification of Aurora-A in many malignant human cancers. The purpose of this study was to investigate the amplification and expression of Aurora-A in esophageal squamous cell carcinoma. Amplification of Aurora-A was determined by fluorescence in situ hybridization in 7 esophageal cancer cell lines and real-time PCR in 29 esophageal cancer samples. We detected Aurora-A expression in 7 esophageal cancer cell lines and 38 esophageal cancers samples by semi-quantitative reverse transcription-PCR and Western blot hybridization. The amplification of Aurora-A was detected in 27 of 29 (93.1%) esophageal cancer samples and 6 of 7 (85.7%) cancer cell lines. Aurora-A was overexpressed in 27 of 38 (71.1%) esophageal cancer samples and all 7 esophageal cancer cell lines. We conclude that Aurora-A is amplified and overexpressed in esophageal squamous cancer.

[Establishment of a model to assess the clinical efficacy of Gefitinib in treatment of non-small cell lung cancer].

OBJECTIVE: To establish a model to predict the clinical response of Gefitinib in non-small cell lung cancer (NSCLC). METHODS: The clinical outcomes of 262 consecutive advanced NSCLC patients to oral treatment of gefitinib 250 mg daily in the past 4 years were reviewed. DNA sequencing was used to detect the mutations in the exons 18, 19, 20, and 21 of the epidermal growth factor receptor (EGFR) tyrosine kinase domain in 55 patients who had enough tumor tissues. RESULTS: The response rate and disease control rate of gefitinib in the advanced NSCLC patients were 30.1% and 78.6% respectively. The median progression free survival and median overall survival were 6.0 and 16.0 months respectively, while the 1, 2 and 3-year survival rates of the NSCLC patients were 60.8%, 35.6%, and 18.3% respectively. The clinical response rate of the patients with EGFR mutation was 50.0%, significantly higher than that of those patients without mutation (16.1%; P = 0.009). In the majority of patients Gefitinib was well tolerated, and the common adverse effects were skin rash and diarrhea. Based on the results of our patients, we try to establish a model which may predict the response of patients by logistic multivariate regression analysis. Patients being female aged under 65, with adenocarcinoma, not smoking, taxone-unresistant and with EGFR mutation were more sensitive to gifitinib. However, COX multivariate regression analysis showed that only the age, histology, smoke status and EGFR mutation were valuable in selection of sensitive patients. So, we set up the cut-off value at 2 in the model based on these 4 factors. The response rate of the patients with 2 or more scores was 34.2%, significantly higher than that of the patients with the scores < 2 (9.3%, P = 0.001). The sensitivity would be doubled when the score increases by one point. CONCLUSION: A simple clinical model based on the patients' age, histology, smoking status and EGFR mutation has been established and is useful to determine the efficacy of gifitinib in NSCLC patients.

[Expression of survivin and its significance in esophageal cancer].

OBJECTIVE: To detect the expression of survivin in esophageal cancer and elucidate its function in esophageal cancer. METHODS: Expression of surviv in was detected in paired normal and tumor tissues from patients with esophageal cancer by semi-quantitative RT-PCR. A dominant-negative survivin (surT34A) was transfected into esophageal cancer EC9706 cells (EC9706surT34A). Colony formation and apoptosis of the parental and surT34A-transfected EC9706 cells were examined in soft agar and by flow cytometry, respectively. RESULTS: Survivin mRNA expression of tumor tissues was higher than normal tissues in 18/27 (66.7%) samples. The expression level of survivin mRNA in tumor tissues (2.08 +/- 1.32) was significantly higher than that in normal tissues (1.22 +/- 1.09). EC9706 surT34A cells formed fewer colonies on agar than the non-transfected ones. After serum withdrawal, EC9706surT34A had higher apoptotic ratio than control, but survivin could reduce the apoptotic ratio. CONCLUSION: Overexpression of survivin is a common eventin esophageal cancer. The dominant-negative survivin can partially inhibit the malignant phenotype of esophageal cancer.

Knockdown of c-Myc expression by RNAi inhibits MCF-7 breast tumor cells growth in vitro and in vivo.

INTRODUCTION: Breast cancer is the leading cause of cancer death in women worldwide. Elevated expression of c-Myc is a frequent genetic abnormality seen in this malignancy. For a better understanding of its role in maintaining the malignant phenotype, we used RNA interference (RNAi) directed against c-Myc in our study. RNAi provides a new, reliable method to investigate gene function and has the potential for gene therapy. The aim of the study was to examine the anti-tumor effects elicited by a decrease in the protein level of c-Myc by RNAi and its possible mechanism of effects in MCF-7 cells. METHOD: A plasmid-based polymerase III promoter system was used to deliver and express short interfering RNA (siRNA) targeting c-myc to reduce its expression in MCF-7 cells. Western blot analysis was used to measure the protein level of c-Myc. We assessed the effects of c-Myc silencing on tumor growth by a growth curve, by soft agar assay and by nude mice experiments in vivo. Standard fluorescence-activated cell sorter analysis and TdT-mediated dUTP nick end labelling assay were used to determine apoptosis of the cells. RESULTS: Our data showed that plasmids expressing siRNA against c-myc markedly and durably reduced its expression in MCF-7 cells by up to 80%, decreased the growth rate of MCF-7 cells, inhibited colony formation in soft agar and significantly reduced tumor growth in nude mice. We also found that depletion of c-Myc in this manner promoted apoptosis of MCF-7 cells upon serum withdrawal. CONCLUSION: c-Myc has a pivotal function in the development of breast cancer. Our data show that decreasing the c-Myc protein level in MCF-7 cells by RNAi could significantly inhibit tumor growth both in vitro and in vivo, and imply the therapeutic potential of RNAi on the treatment of breast cancer by targeting overexpression oncogenes such as c-myc, and c-myc might be a potential therapeutic target for human breast cancer.

[Suppression of c-myc expression by interference RNA in HepG2 hepatocellular carcinoma cells].

OBJECTIVE: To study the inhibitory effect of RNA interference (RNAi) on c-myc expression in hepatocellular carcinoma cell line, HepG2. METHODS: Expression vector of c-myc gene-targeting small interference RNA (siRNA) was constructed (psilencer-c-myc) and transfected into HepG2 cells by lipofectamine, and the unloaded vector was used as control (mock). The expression of c-myc mRNA and protein was identified by quantitive PCR and Western blot. Apoptosis of the transfected cells was examined by flow cytometry and immunofluorescent microscopy. RESULTS: After HepG2 cells were transfected with psilencer-c-myc, the expression of c-myc mRNA and protein was suppressed with an inhibition rate of 67% compared with the mock-transfected cells. Apoptosis was identified in the transfected HepG2 cells. CONCLUSION: The expression of c-myc at transcriptional and translational levels in HepG2 cells transfected with siRNA is markedly inhibited, which may be associated with the induction of apoptosis.

[Indomethacin induces apoptosis through inhibition of survivin regulated by beta-catenin/TCF4 in human colorectal cancer cells].

BACKGROUND & OBJECTIVE: Although Wnt pathway plays important role in colorectal carcinogenesis, but the mechanism of this pathway in anti-apoptosis is not clear. This study is to investigate the molecular mechanism of Wnt pathway in anti-apoptosis. METHODS: Survivin promoter region was constructed into luciferase reporter system (pGL3-sur1.8kb). The recombinants pGL3-sur1.8kb were cotransfected with pRL-SV40 into HCT116 cells and the activities were detected with Dual-luciferase reporter assay system. Cell apoptosis was analyzed by flow cytometry. Protein level of survivin and beta-catenin was detected by Western Blot. RESULTS: Survivin could be up-regulated by beta-catenin and down-regulated by TCF4DeltaN in transcriptional level. beta-catenin/TCF4 dependent apoptosis induced by indomethacin could suppress survivin transcription. Overexpression of survivin could partially recover the beta-catenin/TCF4 dependent apoptosis. CONCLUSION: Down-regulation of survivin affected by beta-catenin/TCF4 pathway plays an important role in apoptosis induced by NSAIDs indomethacin in HCT116 cells. The beta-catenin/TCF4-survivin pathway may be a potential target in treatment of colon cancer.

Down-regulation of gamma-synuclein in human esophageal squamous cell carcinoma.

AIM: To investigate gene expression pattern of human gamma-synuclein gene in human esophageal squamous cell carcinoma (ESCC) by using semi-quantitive reverse transcription polymerase chain reaction (RT-PCR), and to study the role of gamma-synuclein in the development of human ESCC. METHODS: Semi-quantitive RT-PCR of 27 pairs of specimens of human ESCC tissues and corresponding normal tissues was used to investigate the expression pattern of gamma-synuclein in ESCC. 9706/gamma-syn cells in which gamma-synuclein was overexpressed were obtained through cloning gamma-synuclein gene by PCR and transfecting it into ESCC 9706 cells, then selecting with G-418 for 14 days. The biological effects of gamma-synuclein were measured and compared between 9706/gamma-syn and 9706/vec cells by cell growth curve and soft agar assay. RESULTS: RT-PCR showed that gamma-synuclein gene was expressed in all the 27 cases of normal epithelial tissues, while downregulation of gamma-synuclein was observed in 16 out of the 27 cases (59.3 %) of ESCC. There were also 6 cases of ESCC tissues with a high expression level of gamma-synuclein mRNA. In functional analysis we found that over-expression of gamma-synuclein in ESCC 9706 cells could inhibit the growth rate and transformation ability of ESCC 9706 cells. CONCLUSION: The low expression level of gamma-synuclein in human ESCC and the biological effects of gamma-synuclein over-expression on ESCC 9706 cells suggest that gamma-synuclein may play a role as a negative regulator in the development of human ESCC.

Detection of human papillomavirus in Chinese esophageal squamous cell carcinoma and its adjacent normal epithelium.

AIM: To investigate the putative role of human papillomavirus (HPV) infection in the carcinogenesis of esophageal squamous cell carcinoma in China. METHODS: Twenty-three esophageal squamous cell carcinoma samples and the distal normal epithelium from Shanxi Province, and 25 more esophageal squamous cell carcinoma samples from Anyang city, two areas with a high incidence of esophageal cancer in China, were detected for the existence of HPV-16 DNA by PCR, mRNA in situ hybridization (ISH) and immunohistochemistry (IHC) targeting HPV-16 E6 gene. RESULTS: There were approximately 64 % (31/48) patients having HPV-16 DNA in tumor samples, among them nearly two-thirds (19/31) samples were detected with mRNA expression of HPV-16 E6. However, in the normal esophageal epithelium from cancer patients, the DNA and mRNA of HPV-16 were found with much less rate: 34.7 % (8/23) and 26.1 % (6/23) respectively. In addition, at protein level detected by IHC assay, 27.1 % (13/48) tumor samples had virus oncoprotein E6 expression, while only one case of normal epithelium was found positive. CONCLUSION: HPV infection, especially type 16, should be considered as a risk factor for esophageal malignancies in China.

[Survivin mutants reverse the malignancy of HeLa cells].

BACKGROUND & OBJECTIVE: Survivin was aberrantly expressed in most cancer tissues, suggesting that survivin plays an important role in carcinogenesis. This study was designed to investigate the function and mechanism of survivin mutants in tumor cells. METHODS: The site-mutant and truncated survivin mutants were transfected into HeLa cells and selected using G418. Cell apoptosis was analyzed using flow cytometry. Protein level of cyclin D1 was detected by Western blot analysis. RESULTS: Survivin mutant plasmid expressed in the HeLa cells successfully. The expressed protein could be detected using related antibody. Colony formation ability significantly decreased in the HeLa cells with survivin mutants compared with that in the parental HeLa cells. The HeLa cells transfected instantly with survivin mutants could undergo apoptosis automatically. Meanwhile, survivin mutants could cause an increase of multinuclear HeLa cells. The effect of survivin-N showed more effective than that of survivin T34A. Survivin-N and survivin T34A could influence the expression of cyclin D1 and reduced its protein levels of 68% and 12%, respectively. CONCLUSION: Survivin mutants can partially reverse the malignancy of HeLa cells. The reduction of cyclin D1 induced by survivin mutants may play an important role in it. Survivin may be a target gene in gene therapy of cancer.

[Expression and significance of beta-catenin in esophageal carcinoma].

BACKGROUND & OBJECTIVE: Many reports have characterized the aberrant expression of beta-catenin in diverse types of human cancer. To determine whether beta-catenin has possible roles in esophageal carcinogensis, we designed this study to detect the expression pattern of beta-catenin in normal esophageal epithelium and esophageal cancer tissue, then to study the relevance of its expression and localization to tumor differetiation degree and lymph node metastasis. METHODS: By using immunohistochemical staining(SP method), the expression of beta-catenin was detected in 22 normal esophageal tissue slides and 52 esophageal carcinomas. RESULTS: In the 22 normal esophageal tissue, beta-catenin showed high intense expression at the membrane and low intense expression at the cytoplasm. In contrast to the normal tissue, beta-catenin was expressed in the cytoplasma in carcinoma with varied degrees, accompanied by less, or even lost expression at the membrane in cancer samples. In some cases, beta-catenin could be detected in the nucleus. Moreover, the positive rate of beta-catenin expression in cytoplasm was significantly higher in those patients with lymph node metastasis than patients without(P < 0.05). CONCLUSIONS: The aberrant expression of beta-catenin occurred frequently in the esophageal carcinoma, mainly including the translocation of beta-catenin protein from membrane to the cytoplasm and nucleus, and the accumulation of beta-catenin in cytoplasma was overt. And the aberrant expression of beta-catenin protein was statistically correlated to the lymph node metastasis in esophageal cancer.