Jiaoli Guo

miR-200b and miR-200c as Prognostic Factors and Mediators of Gastric Cancer Cell Progression

Purpose: The purpose of this study was to investigate the clinicopathologic significance and potential role of miR-200b and miR-200c in the development and progression of gastric cancer. Experimental Design: We examined miR-200b and miR-200c expression in 36 paired normal and stomach tumor specimens, as well as gastric cancer cell lines, by quantitative real-time PCR. In addition, miR-200b and miR-200c were detected by ISH using gastric cancer tissue microarrays, and the association between miR-200b and miR-200c levels and clinicopathologic factors and prognosis were analyzed. A luciferase assay was conducted for target evaluation. The functional effects of miR-200b and miR-200c on gastric cancer cells were validated by a cell proliferation assay and cell invasion and migration assays. Results: miR-200b and miR-200c were downregulated in the gastric cancer specimens and cell lines tested. miR-200b and miR-200c levels were significantly correlated with the clinical stage, T stage, lymph node metastasis, and survival of patients. Ectopic expression of miR-200b and miR-200c impaired cell growth and invasion. In addition, when overexpressed, miR-200b and miR-200c commonly directly targeted DNMT3A, DNMT3B, and SP1 (a transactivator of the DNMT1 gene), which resulted in marked reduction of the expression of DNA methyltransferases DNMT1, DNMT3A, and DNMT3B at the protein level. This effect, in turn, led to a decrease in global DNA methylation and reexpression of p16, RASS1A1, and E-cadherin via promoter DNA hypomethylation. Conclusion: Our findings suggest that miR-200b and miR-200c, as valuable markers of gastric cancer prognosis, may be a promising approach to human gastric cancer treatment. Clin Cancer Res; 19(20); 5602–12. ©2013 AACR.

Diallyl disulfide suppresses proliferation and induces apoptosis in human gastric cancer through Wnt-1 signaling pathway by up-regulation of miR-200b and miR-22.

The purpose of this study was to identify a mechanism related to miRNA pathway which plays a role in the anti-tumor effects of Diallyl disulfide. Alterations in miRNA expression were observed in Diallyl disulfide-treated MGC-803 cells, including up-regulation of miR-200b and miR-22 expression. Furthermore, Wnt-1 was identified as a target of both miR-200b and miR-22. MiR-200b and miR-22 not only synergistically inhibited gastric cancer growth, but also enhanced the antitumor effect of Diallyl disulfide both in vitro and in vivo. It indicated that miR-200b and miR-22 may serve as potential gene therapy and enhance Diallyl disulfide antitumor effects.

MiR-26a inhibits proliferation and migration of breast cancer through repression of MCL-1.

Breast cancer is the most commonly malignancies in women. MicroRNAs are a family of small non-coding RNAs 18–25 nucleotides in length that post-transcriptionally modulate gene expression. MiR-26a has been reported as a tumor suppressor microRNA in breast cancer, which is attributed mainly to targeting of MTDH and EZH2, however, the expression profile and therapeutic potential of miR-26a is still unclear. Here we demonstrate that miR-26a is down-regulated in breast cancer cells and clinical specimens and its modulation in breast cancer cells regulates cell proliferation, colony formation, migration and apoptosis. MCL-1, an anti-apoptotic member of the Bcl-2 family, as novel targets of miR-26a was found to be in reverse correlation with ectopic expression of miR-26a and knockdown of MCL-1 phenocopied the effect of miR-26a in breast cancer cell lines. It was further explored that miR-26a increased sensitivity of breast cancer cells to paclitaxel in which MCL-1 was involved. Thus, miR-26a impacts on cell proliferation and migration of breast cancer by regulating several carcinogenesis-related processes, including a novel mechanism involving the targeting of MCL-1.

Microrna-124 targets flotillin-1 to regulate proliferation and migration in breast cancer

BackgroundMicroRNAs (miRNAs) have been documented as playing important roles in cancer development. In this study, we investigated the role of miR-124 in breast cancer and clarified the regulation of flotillin-1 (FLOT1) by miR-124.MethodsThe expression levels of miR-124 were examined in breast cancer cell lines and patient specimens using quantitative reverse transcription-PCR. The clinicopathological significance of the resultant data was later analyzed. Next, we explored the function of miR-124 to determine its potential roles on cancer cell growth and migration in vitro. A luciferase reporter assay was conducted to confirm the target gene of miR-124, and the results were validated in cell lines and patient specimens.ResultsWe found that miR-124 expression was significantly downregulated in breast cancer cell lines and patient specimen compared with normal cell lines and paired adjacent normal tissues (P < 0.0001), respectively. MiR-124 was also associated with tumor node metastasis (TNM) stage (P = 0.0007) and lymph node metastasis (P = 0.0004). In breast cancer cell lines, the ectopic expression of miR-124 inhibited cell growth and migration in vitro. Moreover, we identified the FLOT1 gene as a novel direct target of miR-124, and miR-124 ectopic expression significantly inhibited FLOT1. Luciferase assays confirmed that miR-124 could directly bind to the 3′ untranslated region of FLOT1 and suppress translation. Moreover, FLOT1 was widely upregulated, and inversely correlated with miR-124 in breast cancer tissues. Consistent with the effect of miR-124, the knockdown of FLOT1 significantly inhibited breast cancer cell growth and migration. We also observed that the rescue expression of FLOT1 partially restored the effects of miR-124.ConclusionsOur study demonstrated that miR-124 might be a tumor suppressor in breast cancer via the regulation of FLOT1. This microRNA could serve as a potential diagnostic marker and therapeutic target for breast cancer.

Targeted expression of miR-34a using the T-VISA system suppresses breast cancer cell growth and invasion

Recurrence and metastasis result in a poor prognosis for breast cancer patients. Recent studies have demonstrated that microRNAs (miRNAs) play vital roles in the development and metastasis of breast cancer. In this study, we investigated the therapeutic potential of miR-34a in breast cancer. We found that miR-34a is downregulated in breast cancer cell lines and tissues, compared with normal cell lines and the adjacent nontumor tissues, respectively. To explore the therapeutic potential of miR-34a, we designed a targeted miR-34a expression plasmid (T-VISA-miR-34a) using the T-VISA system, and evaluated its antitumor effects, efficacy, mechanism of action, and systemic toxicity. T-VISA-miR-34a induced robust, persistent expression of miR-34a, and dramatically suppressed breast cancer cell growth, migration, and invasion in vitro by downregulating the protein expression levels of the miR-34a target genes E2F3, CD44, and SIRT1. In an orthotopic mouse model of breast cancer, intravenous injection of T-VISA-miR-34a:liposomal complex nanoparticles significantly inhibited tumor growth, prolonged survival, and did not induce systemic toxicity. In conclusion, T-VISA-miR-34a lead to robust, specific overexpression of miR-34a in breast cancer cells and induced potent antitumor effects in vitro and in vivo. T-VISA-miR-34a may provide a potentially useful, specific, and safe-targeted therapeutic approach for breast cancer.

Synergistic effects of curcumin with emodin against the proliferation and invasion of breast cancer cells through upregulation of miR-34a

Curcumin, a biphenyl compound derived from rhizome, is a powerful anti-cancer agent. Emodin is an active component isolated from the root and rhizome of Rheumpalmatum that has been widely used in traditional Chinese medicine for the treatment of various diseases. Currently, there are no studies examining the effect of curcumin in combination with emodin on tumor cell growth. In this study, we report for the first time that combined curcumin and emodin administration synergistically inhibits proliferation (MTT assay), survival (flow cytometry), and invasion (transwell migration assay) of breast cancer cells. Synergism is determined by the Chou–Talalay method. Moreover, we demonstrate that miR-34a is upregulated by curcumin and emodin. This microRNA helps mediate the anti-tumor effects of curcumin and emodin by downregulating Bcl-2 and Bmi-1. Our results not only provide insight into the mechanism of synergy between curcumin and emodin in breast cancer cells, but also suggest a new and potentially useful approach for breast cancer therapy.

Targeted Expression of BikDD Eliminates Breast Cancer with Virtually No Toxicity in Noninvasive Imaging Models

Breast cancer is a major public health problem all over the world, and the current treatment strategies are not potent enough for some patients, especially those with triple-negative breast cancer. Therefore, novel and more effective treatments are critically needed. Of the current methods, targeted therapy, which not only retains cancer-specific expression but also limits toxicity, is a new strategy for treating cancers. In this study, we found that the human telomerase reverse transcriptase (hTERT; T) promoter also possesses high target specificity in breast cancer. Moreover, we developed a versatile T-based breast cancer–specific promoter VISA (VP16-Gal4-WPRE integrated systemic amplifier) composite (T-VISA) to target transgene expression in breast tumors, which has stronger activity comparable or higher than that of the cytomegalovirus promoter in cancer cells. Thereafter, targeted expression of BikDD (a mutant form of proapoptotic gene Bik) through the T-VISA platform in breast cancer initiated robust antitumor effects and prolonged survival in multiple xenograft and syngeneic orthotopic mouse models of breast tumors with virtually no toxicity in intact mice. Thus, these findings show that our T-VISA-BikDD nanoparticles effectively and safely eradicate breast cancer in vitro and in vivo and are worthy of development in clinical trials treating breast cancer. Mol Cancer Ther; 11(9); 1915–24. ©2012 AACR.

Targeted expression of Escherichia coli purine nucleoside phosphorylase and Fludara® for prostate cancer therapy: PNP/Fludara for prostate cancer gene therapy

Previous studies have shown that Herpes Simplex Virus thymidine kinase (HSV‐tk)/ganciclovir (GCV) comprised the most commonly used suicide gene therapy for prostate cancer, with modest results being obtained. However, novel suicide genes, such as Escherichia coli purine nucleoside phosphorylase (PNP), have been utilized to demonstrate more potent tumor killing and an enhanced bystander effect on local, non‐expressing cells compared to HSV‐tk.

Erratum: Targeted expression of Escherichia coli purine nucleoside phosphorylase and Fludara® for prostate cancer therapy

*Correspondence to: X. Xie or W. Wei, State Key Laboratory of Oncology in South China, Department of Breast Oncology, Sun Yat-Sen University Cancer Center, 651 East Dongfeng Road, Guangzhou, 510060, People’s Republic of China or David M Spencer, Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas 77030, USA. E-mail: xiexm@sysucc.org.cn or weiwd @sysucc.org.cn or dspencer@bcm.edu Both investigators contributed equally and should be considered as senior authors.

Cytokeratin19-2g2, a Novel Fragment of Cytokeratin19 in Serum, Indicating a More Invasive Behavior and Worse Prognosis in Breast Cancer Patients

Background Various studies have been searching for new tumor biomarkers for breast cancer for years. However, so far, few markers have been proved clinically useful except CA153. Based on knowledge that most adenocarcinomas including breast carcinoma expressed Cytokeratin19, the authors studied CK19-2G2,a novel fragment of cytokeratin19 shedding into serum in breast cancer patients. Patients and Methods The serum samples of four hundred and seventeen patients including three hundred and three (fifty-four DCIS and two hundred and forty-nine stage I-III) PBC patients and one hundred and fourteen MBC patients, eighty-one healthy controls and twenty-one breast benign disease patients were provided for measurement of CK19-2G2, CEA and CA153.The correlation between clinicopathological characters, prognosis and CK19-2G2 levels was further studied. Results The serum CK19-2G2 levels in breast cancer patients were significantly higher than that in healthy and benign controls. For breast cancer patients, CK19-2G2 levels in MBC were significantly higher than that in PBC patients. The sensitivities of CK19-2G2 for breast carcinoma are as high as CEA and CA153, and up to 71% in MBC patients. Serum CK19-2G2 levels (≥2 mU/mL) were associated with pathological stages, tumor size (≥2 cm), lymph node involvement, and HER2 status. Multivariate analysis revealed that high serum CK19-2G2 level was an independent factor for relapse (P = 0.029) and death (P = 0.040) in breast cancer patients. Conclusion Serum CK19-2G2 may be an independent indicator for prognosis and a candidate marker for monitoring metastasis in breast cancer.