Targeting Survivin Enhances Chemosensitivity in Retinoblastoma Cells and Orthotopic Tumors

Treatments for retinoblastoma (Rb) vary depending on the size and location of the intraocular lesions and include chemotherapy and radiation therapy. We examined whether agents used to treat Rb induce a pro-survival phenotype associated with increased expression of survivin, a member of the inhibitor of apoptosis family of proteins. We document that exposure to carboplatin, topotecan or radiation resulted in elevated expression of survivin in two human Rb cell lines but not in normal retinal pigmented epithelial (RPE) cells. Cellular levels of survivin were attenuated in Rb cells exposed to an imidazolium-based survivin suppressant, Sepantronium bromide (YM155). Protein expression patterns of survivin in RPE cells were not altered following treatment protocols involving exposure to YM155. Including YM155 with chemotherapy or radiation increased levels of apoptosis in Rb cells but not in RPE cells. Intraocular luciferase expressing Rb tumors were generated from the Rb cell lines and used to evaluate the effects of carboplatin and YM155 on in-vivo survivin expression and tumor growth. Carboplatin induced expression of survivin while carboplatin combined with YM155 reduced survivin expression in tumor bearing eyes. The combination protocol was also most effective in reducing the rate of tumor regrowth. These results indicate that targeted inhibition of the anti-apoptotic protein survivin provides a therapeutic advantage for Rb cells and tumors treated with chemotherapy.     

Arctigenin Enhances Chemosensitivity to Cisplatin in Human Nonsmall Lung Cancer H460 Cells through Downregulation of Survivin Expression

Arctigenin, a dibenzylbutyrolactone lignan, enhances cisplatin‐mediated cell apoptosis in cancer cells. Here, we sought to investigate the effects of arctigenin on cisplatin‐treated non‐small‐cell lung cancer (NSCLC) H460 cells. The 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay and annexin‐V/propidium iodide staining were performed to analyze the proliferation and apoptosis of H460 cells. Arctigenin dose‐dependently suppressed cell proliferation and potentiated cell apoptosis, coupled with increased cleavage of caspase‐3 and poly(ADP‐ribose) polymerase. Moreover, arctigenin sensitized H460 cells to cisplatin‐induced proliferation inhibition and apoptosis. Arctigenin alone or in combination with cisplatin had a significantly lower amount of survivin. Ectopic expression of survivin decreased cell apoptosis induced by arctigenin (P < 0.05) or in combination with cisplatin (P < 0.01). Moreover, arctigenin (P < 0.05) or in combination with cisplatin (P < 0.01) induced G1/G0 cell‐cycle arrest. Our data provide evidence that arctigenin has a therapeutic potential in combina‐tion with chemotherapeutic agents for NSLC.     

MicroRNA-1280 Inhibits Invasion and Metastasis by Targeting ROCK1 in Bladder Cancer

MicroRNAs (miRNAs) are non-protein-coding sequences that can function as oncogenes or tumor suppressor genes. This study documents the tumor suppressor role of miR-1280 in bladder cancer. Quantitative real-time PCR and in situ hybridization analyses showed that miR-1280 is significantly down-regulated in bladder cancer cell lines and tumors compared to a non-malignant cell line or normal tissue samples. To decipher the functional significance of miR-1280 in bladder cancer, we ectopically over-expressed miR-1280 in bladder cancer cell lines. Over-expression of miR-1280 had antiproliferative effects and impaired colony formation of bladder cancer cell lines. FACS (fluorescence activated cell sorting) analysis revealed that re-expression of miR-1280 in bladder cancer cells induced G2-M cell cycle arrest and apoptosis. Our results demonstrate that miR-1280 inhibited migration and invasion of bladder cancer cell lines. miR-1280 also attenuated ROCK1 and RhoC protein expression. Luciferase reporter assays demonstrated that oncogene ROCK1 is a direct target of miR-1280 in bladder cancer. This study also indicates that miR-1280 may be of diagnostic and prognostic importance in bladder cancer. For instance, ROC analysis showed that miR-1280 expression can distinguish between malignant and normal bladder cancer cases and Kaplan-Meier analysis revealed that patients with miR-1280 high expression had higher overall survival compared to those with low miR-1280 expression. In conclusion, this is the first study to document that miR-1280 functions as a tumor suppressor by targeting oncogene ROCK1 to invasion/migration and metastasis. Various compounds are currently being used as ROCK1 inhibitors; therefore restoration of tumor suppressor miR-1280 might be therapeutically useful either alone or in combination with these compounds in the treatment of bladder cancer.     

MicroRNA-155 Regulates Cell Survival,Growth, and Chemosensitivity by Targeting FOXO3a in Breast Cancer

Breast cancer is the second leading cause of cancer death in women. Despite improvement in treatment over the past few decades, there is an urgent need for development of targeted therapies. miR-155 (microRNA-155) is frequently up-regulated in breast cancer. In this study, we demonstrate the critical role of miR-155 in regulation of cell survival and chemosensitivity through down-regulation of FOXO3a in breast cancer. Ectopic expression of miR-155 induces cell survival and chemoresistance to multiple agents, whereas knockdown of miR-155 renders cells to apoptosis and enhances chemosensitivity. Further, we identified FOXO3a as a direct target of miR-155. Sustained overexpression of miR-155 resulted in repression of FOXO3a protein without changing mRNA levels, and knockdown of miR-155 increases FOXO3a. Introduction of FOXO3a cDNA lacking the 3′-untranslated region abrogates miR-155-induced cell survival and chemoresistance. Finally, inverse correlation between miR-155 and FOXO3a levels were observed in a panel of breast cancer cell lines and tumors. In conclusion, our study reveals a molecular link between miR-155 and FOXO3a and presents evidence that miR-155 is a critical therapeutic target in breast cancer.     

MicroRNA-214 Suppresses Oncogenesis and Exerts Impact on Prognosis by Targeting PDRG1 in Bladder Cancer

MicroRNA-214 (miR-214) has been reported to be dysregulated in human bladder cancer tissues. We aimed to investigate the clinical correlation, biological significance and molecular network of miR-214 in bladder cancer. Our results showed miR-214 was down-regulated in bladder cancer tissues and significantly associated with tumor stage, lymph node status, grade, multifocality, history of non-muscle-invasive bladder cancer (NMIBC). Moreover, miR-214 could serve as an independent factor of recurrence-free survival (RFS) and overall survival (OS) for patients with muscle-invasive bladder cancer (MIBC). Restoration of miR-214 expression in bladder cancer cell lines inhibited cell proliferation, migration, invasion and markedly promoted apoptosis. Dual-luciferase reporter assay recognized PDRG1 as direct downstream target gene of miR-214. PDRG1 was significantly increased in tumors low of miR-214 and knockdown of PDRG1 mimicked the effects of miR-214 overexpression. Our findings manifest that miR-214 could exert tumor-suppressive effects in bladder cancer by directly down-regulating oncogene PDRG1 and suggest an appealing novel indicator for prognostic and therapeutic intervention of bladder cancer.     

Prognostic Role of Survivin in Bladder Cancer: A Systematic Review and Meta-Analysis

Purpose

The objective of the present study was to conduct a systematic review and meta-analysis of published literature investigating the survivin expression and its effects on bladder cancer prognosis.

Materials and Methods

We carefully searched online Pubmed, Cochrane Library and SCOPUS database from August 1997 to May 2013.

Results

A total of 14 articles met the eligibility criteria for this systematic review. The eligible studies included a total of 2,165 patients with a median number of 155 patients per study (range: 17–726). Of the 14 studies, nine evaluated immunohistochemistry in formalin-fixed paraffin-embedded tissue blocks. In non-muscle invasive bladder tumor, the pooled hazard ratio (HR) was statistically significant for recurrence-free survival (pooled HR, 1.81; 95% confidence interval [CI], 1.30–2.52), progression-free survival (pooled HR, 2.12; 95% CI, 1.60–2.82), cancer-specific survival (pooled HR, 2.01; 95% CI, 1.32–3.06), and overall survival (pooled HR, 1.53; 95% CI, 1.02–2.29). The overall HRs by survivin status were robust across advanced stages. When only adjusted survival data were included, statistically significant differences were identified for all survival subgroup analyses. There was no between-study heterogeneity in the effect of survivin status on the majority of meta-analyses. There was no clear evidence of publication bias in this meta-analysis.

Conclusions

Survivin expression indicates worse prognosis in patients with bladder cancer but the results should be interpreted with caution. It is necessary that better-designed studies with standardized assays need to provide a better conclusion about the relationship between survivin expression and the outcome of patients with bladder cancer.     

Low Expression of Smurf1 Enhances the Chemosensitivity of Human Colorectal Cancer to Gemcitabine and Cisplatin in Patient-Derived Xenograft Models

Despite the side effects, chemotherapy is one of the most common treatments in colorectal cancer (CRC). An open-ended question about CRC chemotherapy, which has been discussed quite often, is with respect to the validation of prognostic or predictive factors. It is believed that personalized chemotherapy can improve the treatment outcome of patients with colorectal tumors. Though, Smurf1 is highly expressed in multiple tumors and plays a critical role in the occurrence and development of multiple cancers, it’s role in the susceptibility of CRC response to chemotherapy is still unknown, Therefore, the study aimed to understand the role of Smurf1 in the susceptibility of CRC response to chemotherapy. The study showed that the knockdown of Smurf1 increases gemcitabine and cisplatin-induced HCT116 cells apoptosis in vitro. Furthermore, in vivo experiments showed that tumors that had low Smurf1 expression exhibited enhanced gemcitabine, cisplatin, and gemcitabine plus cisplatin anti-tumor effects in HCT116 cell-derived xenograft (CDX) models and patient-derived xenograft (PDX) models. In conclusion, the results indicated that Smurf1 inhibits the chemosensitivity of CRC to gemcitabine, cisplatin, and gemcitabine plus cisplatin. Therefore, downregulati1ng the Smurf1 expression is a potential strategy to increase the efficacy of gemcitabine and cisplatin in CRC patients.     

MicroRNA-576-3p Inhibits Proliferation in Bladder Cancer Cells by Targeting Cyclin D1

MicroRNAs (miRNAs) are small, endogenous RNAs that play important gene-regulatory roles by binding to the imperfectly complementary sequences at the 3′-UTR of mRNAs and directing their gene expression. Here, we first discovered that miR-576-3p was down-regulated in human bladder cancer cell lines compared with the non-malignant cell line. To better characterize the role of miR-576-3p in bladder cancer cells, we over-expressed or down-regulated miR-576-3p in bladder cancer cells by transfecting with chemically synthesized mimic or inhibitor. The overexpression of miR-576-3p remarkably inhibited cell proliferation via G1-phase arrest, and decreased both mRNA and protein levels of cyclin D1 which played a key role in G1/S phase transition. The knock-down of miR-576-3p significantly promoted the proliferation of bladder cancer cells by accelerating the progression of cell cycle and increased the expression of cyclin D1. Moreover, the dual-luciferase reporter assays indicated that miR-576-3p could directly target cyclin D1 through binding its 3′-UTR. All the results demonstrated that miR-576-3p might be a novel suppressor of bladder cancer cell proliferation through targeting cyclin D1.     

抑制 Livin 基因对肺腺癌 SPC-A1 细胞增殖及顺铂敏感性的影响

目的:Livin是近年来发现的人类凋亡抑制蛋白(inhibitorof apoptosis protein,IAP)家族的新成员,发现在多数肿瘤中表达,与肿瘤发生有密切关系,并可能作为肿瘤诱导凋亡治疗的新靶点。本研究旨在探讨si RNA-Livin和夫拉平度(Flavopiridol,FP)协同凋亡诱导配体(TRAIL)两种方式有效抑制Livin表达,诱导非小细胞肺癌SPC-A1凋亡并增强对化疗药物顺铂的敏感性。方法:si RNA-Livin转染SPC-A1,Real-Time PCR检测Livin基因的表达水平,MTT检测干扰组和干扰加药组肿瘤细胞的增殖及活性;TRAIL、FP单独及联合作用诱导细胞凋亡,蛋白质印迹法检测凋亡抑制蛋白Livin的表达水平,MTT检测各处理组细胞的增殖及活性。结果:100 nmol/LFP处理组(F)细胞存活率为(84.30±1.34)%,100 ng/m LTRAIL处理组(T)为(93.40±1.56)%,FP和TRAIL联合组(F+T)为(48.02±1.35)%,si RNA-Livin处理组为(50.88±1.14)%,1.2μg/m L Cisplatin处理组为(19.30±0.89)%,si RNA-livin+Cisplatin组为(14.37±0.81)%,FP+T+Cisplatin组为(10.86±0.87)%,C组存活率为100%。F+T组对细胞的增殖抑制作用显著高于单独用药组,si RNA-livin+Cisplatin与si RNA-Livin组相比、FP+T+Cisplatin与FP+T组相比都显著增强了化疗药物对SPC-A1的杀伤作用。50μmol/LZ-VAD-FMK预处理后联合用药组细胞的存活率为(88.16±1.64)%,caspase抑制剂能明显抑制F+T联合处理组的凋亡效应。结论:RNA干扰和F+T联合用药都能显著降低凋亡抑制蛋白Livin的表达,有效抑制肿瘤细胞的增殖生长,并增强肿瘤细胞对化疗药物顺铂的敏感性,为肺腺癌的靶向治疗提供新的理论依据。     

Piceatannol Enhances Cisplatin Sensitivity in Ovarian Cancer via Modulation of p53, X-linked Inhibitor of Apoptosis Protein (XIAP), and Mitochondrial Fission

Resistance to cisplatin (CDDP) in ovarian cancer (OVCA) arises from the dysregulation of tumor suppressors and survival signals. During genotoxic challenge, these factors can be influenced by secondary agents that facilitate the induction of apoptosis. Piceatannol is a natural metabolite of the stilbene resveratrol found in grapes and is converted from its parent compound by the enzyme CYP1BA1 p450. It has been hypothesized to exert specific effects against various cellular targets; however, its ability to influence CDDP resistance in cancer cells has not been investigated to date. Here, we show that piceatannol is a potent enhancer of CDDP sensitivity in OVCA, and this effect is achieved through the modulation of several major determinants of chemoresistance. Piceatannol enhances p53-mediated expression of the pro-apoptotic protein NOXA, increases XIAP degradation via the ubiquitin-proteasome pathway, and enhances caspase-3 activation. This response is associated with an increase in Drp1-dependent mitochondrial fission, leading to more effective induction of apoptosis. In vivo studies using a mouse model of OVCA reveal that a number of these changes occur in association with a greater overall reduction in tumor weight when mice are treated with both piceatannol and CDDP, in comparison to treatment with either agent alone. Taken together, these findings demonstrate the potential application of piceatannol to enhance CDDP sensitivity in OVCA, and it acts on p53, XIAP, and mitochondrial fission.     

MicroRNA-302a Functions as a Putative Tumor Suppressor in Colon Cancer by Targeting Akt

Micro RNAs (miRNAs) are important regulators involved in various physical and pathological processes, including cancer. The miRNA-302 family has been documented as playing a critical role in carcinogenesis. In this study, we investigated the role of miRNA-302a in colon cancer. MiRNA-302a expression was detected in 44 colon cancer tissues and 10 normal colon tissues, and their clinicopathological significance was analyzed. Cell proliferation and cell cycle analysis were performed on colon cancer cells that stably expressed miRNA-302a. The target gene of miRNA-302a and the downstream pathway were further investigated. Compared with normal colon tissues, miRNA-302a expression was downregulated in colon cancer tissues. Overexpression of miRNA-302a induced G1/S cell cycle arrest in colon cancer cells, and suppressed colon cancer cell proliferation both in vitro and in vivo. Furthermore, miRNA-302a inhibited AKT expression by directly binding to its 3′ untranslated region, resulting in subsequent alterations of the AKT-GSK3β-cyclin D1 pathway. These results reveal miRNA-302a as a tumor suppressor in colon cancer, suggesting that miRNA-302a may be used as a potential target for therapeutic intervention in colon cancer.     

MicroRNA-137 Contributes to Dampened Tumorigenesis in Human Gastric Cancer by Targeting AKT2

MiRNAs play important roles in tumorigenesis. This study focused on exploring the effects and regulation mechanism of miRNA-137 on the biological behaviors of gastric cancer. Total RNA was extracted from tissues of 100 patients with gastric cancer and from four gastric cancer cell lines. Expression of miR-137 was detected by real-time PCR from 100 patients. The effects of miR-137 overexpression on gastric cancer cells’ proliferation, apoptosis, migration and invasion ability were investigated in vitro and in vivo. The target gene of miR-137 was predicted by Targetscan on line software, screened by dual luciferase reporter gene assay and demonstrated by western blot. As a result, the expression of miR-137 was significant reduced in gastric cancer cell line HGC-27, HGC-803, SGC-7901 and MKN-45 as well as in gastric cancer tissues compared with GES-1 cell or matched adjacent non-neoplastic tissues (p<0.001). The re-introduction of miR-137 into gastric cancer cells was able to inhibit cell proliferation, migration and invasion. The in vivo experiments demonstrated that the miR-137 overexpression can reduce the gastric cancer cell proliferation and metastasis. Bioinformatic and western blot analysis indicated that the miR-137 acted as tumor suppressor roles on gastric cancer cells through targeting AKT2 and further affecting the Bad and GSK-3β. In conclusion, the miR-137 which is frequently down-regulated in gastric cancer is potentially involved in gastric cancer tumorigenesis and metastasis by regulating AKT2 related signal pathways.