Shiying Yu

Notch signaling: An emerging therapeutic target for cancer treatment.

The Notch pathway is involved in cell proliferation, differentiation and survival. The Notch signaling pathway is one of the most commonly activated signaling pathways in cancer. Alterations include activating mutations and amplification of the Notch pathway, which play key roles in the progression of cancer. Accumulating evidence suggests that the pharmacological inhibition of this pathway can overcome chemoresistance. Efforts have been taken to develop Notch inhibitors as a single agent or in combination with clinically used chemotherapeutics to treat cancer. Some Notch inhibitors have been demonstrated to have therapeutic efficacy in preclinical studies. This review summarizes the recent studies and clinical evaluations of the Notch inhibitors in cancer.

Notch signaling and EMT in non-small cell lung cancer: biological significance and therapeutic application

Through epithelial-mesenchymal transition (EMT), cancer cells acquire enhanced ability of migration and invasion, stem cell like characteristics and therapeutic resistance. Notch signaling regulates cell-cell connection, cell polarity and motility during organ development. Recent studies demonstrate that Notch signaling plays an important role in lung cancer initiation and cross-talks with several transcriptional factors to enhance EMT, contributing to the progression of non-small cell lung cancer (NSCLC). Correspondingly, blocking of Notch signaling inhibits NSCLC migration and tumor growth by reversing EMT. Clinical trials have showed promising effect in some cancer patients received treatment with Notch1 inhibitor. This review attempts to provide an overview of the Notch signal in NSCLC: its biological significance and therapeutic application.

MicroRNA-10b targets E-cadherin and modulates breast cancer metastasis.

Summary Background Recent studies have suggested that microRNA-10b (miR-10b) acts as a promoter of metastasis in breast cancer, although the underlying mechanism remains largely unknown. In this study, we provide the first evidence that E-cadherin (E-cad) is a potential target of miR-10b. Material/Method By applying gain-of-function and loss-of-function approaches in the metastatic breast cancer cell line MDA-MB-231, we demonstrated that miR-10b is necessary and sufficient to regulate the cellular expression of E-cad and in vitro tumor cell invasion. Results Comparative expression analysis of miR-10b in benign breast lesions (N=16), primary breast cancers (N=21), and metastatic breast carcinomas (N=23) revealed that miR-10b transcription was uniquely up-regulated in metastatic cancers. The expression level of miR-10b positively correlated with tumor size, pathological grading, clinical staging, lymph node metastasis, Her2-positivity and tumor proliferation, but was negatively associated with estrogen receptor-positivity, progesterone receptor-positivity and E-cad mRNA and protein levels. Conclusions These findings indicate the existence of a novel E-cadherin-related mechanism by which miR-10b modulates breast cancer metastasis. In addition, miR-10b may be a useful biomarker of advanced progression and metastasis of breast cancer.

Meta-analysis reveals the correlation of Notch signaling with non-small cell lung cancer progression and prognosis

Various studies have assessed the clinicopathological and prognostic value of Notch1 and Notch3 expression in Non-small cell lung cancer (NSCLC), but their results remain controversial. This meta-analysis was conducted to address the above issues by using a total of 19 studies involving 3663 patients. The correlations between Notch1 and Notch3 expression and clinicopathological features and NSCLC prognosis were analyzed. The meta-analysis indicated that higher expression of Notch1 was associated with greater possibility of lymph node metastasis and higher TNM stages. Moreover, patients with Notch1 overexpression and Notch3 overexpression showed significantly poor overall survival (Notch1: HR, 1.29; 95% CI, 1.06–1.57, p = 0.468 and I2 = 0.0%; Notch3: HR, 1.57; 95%CI, 1.04-2.36, p = 0.445 and I2 = 0.0%). Furthermore, there are statistically significant association between overall survival of NSCLC patients and the expression of Notch signaling ligand DLL3 and target gene HES1. Our meta-analysis supports that Notch signaling is a valuable bio-marker to predict progression and targeting Notch signaling could benefit subpopulation of NSCLC patients.

Activated PI3K/Akt/COX-2 Pathway Induces Resistance to Radiation in Human Cervical Cancer HeLa Cells

Activation of Akt, or protein kinase B, is frequently observed in human cancers. It has been demonstrated that PI3K activation leads to radiation resistance. Here, the role of PI3K/Akt/COX-2 pathway in the resistance to radiation in human cervical cancer HeLa cells is explored. Cultured HeLa cells were randomly assigned to five treatment groups: control, radiation, LY294002, PI3K antagonist, and the COX-2-antagonist celecoxib, with the objective of determining the role of PI3K/Akt/COX-2 pathway in the radiation resistance of HeLa cells. The cell survival ratios were computed by clone formation. To calculate the quasi-threshold dose (Dq), mean lethal dose (D(0)), survival fraction at 2 Gy radiation dose (SF(2)), and radiosensitization ratio, the cell survival curves were fitted to the one-hit multitarget model. The protein expression profiles for pAkt, Akt, COX-2, Bad, and pBad were detected by Western blot analysis, and the mRNA expression profiles for COX-2 and Bad were analyzed by RT-polymerase chain reaction. Treatment with a combination of celecoxib, LY294002, and radiation resulted in elevated Dq, D(0), and SF(2), and increased radiosensitivity in HeLa cells. The PI3K/Akt/COX-2 pathway was activated by radiation, whereas celecoxib inhibited the activation of the PI3K/Akt/COX-2 axis through several targets. Our results indicate that the activated PI3K/Akt/COX-2 signal transduction pathway was the main cause for decline in radiosensitivity in HeLa cells. This study proposes that the inhibition of the PI3K/Akt/COX-2 pathway can synergistically enhance radiation efficacy.

DACH1 inhibits cyclin D1 expression, cellular proliferation and tumor growth of renal cancer cells.

BackgroundRenal cell carcinoma (RCC) is a complex with diverse biological characteristics and distinct molecular signature. New target therapies to molecules that drive RCC initiation and progression have achieved promising responses in some patients, but the total effective rate is still far from satisfaction. Dachshund (DACH1) network is a key signaling pathway for kidney development and has recently been identified as a tumor suppressor in several cancer types. However, its role in renal cell carcinoma has not been fully investigated.MethodsImmunohistochemical staining for DACH1, PCNA and cyclin D1 was performed on human renal tissue microaraays and correlation with clinic-pathological characteristics was analyzed. In vitro proliferation, apoptosis and in vivo tumor growth were evaluated on human renal cancer cell lines with decitabine treatment or ectopic expression of DACH1. Downstream targets and potential molecular mechanism were investigated through western blot, immunoprecipitation and reporter gene assays.ResultsExpression of DACH1 was significantly decreased in human renal carcinoma tissue. DACH1 protein abundance was inversely correlated with the expression of PCNA and cyclin D1, tumor grade, and TNM stage. Restoration of DACH1 function in renal clear cell cancer cells inhibited in vitro cellular proliferation, S phase progression, clone formation, and in vivo tumor growth. In mechanism, DACH1 repressed cyclin D1 transcription through association with AP-1 protein.ConclusionOur results indicated that DACH1 was a novel molecular marker of RCC and it attributed to the malignant behavior of renal cancer cells. Re-activation of DACH1 may represent a potential therapeutic strategy.

Expression of Notch1 Correlates with Breast Cancer Progression and Prognosis

Various studies have evaluated the significance of Notch1 expression in breast cancer, but the results have ever been disputed. By using 21 studies involving 3867 patients, this meta-analysis revealed that the expression of Notch1 was significantly higher in breast cancer than in normal tissues (OR=7.21; 95%CI, 4.7-11.07) and that higher Notch1 expression was associated with transition from ductal carcinoma in situ (DCIS) to invasive cancer (OR=3.75; 95% CI, 1.8-7.78). Higher Notch1 activity was observed in the basal subtype of breast cancer (OR=2.53; 95% CI, 1.18-5.43). Moreover, patients with Notch1 overexpression exhibited significantly worse overall and recurrence-free survival. Our meta-analysis suggests that Notch inhibitors may be useful in blocking the early progression of DCIS and that the outcomes of clinical trials for Notch1-targeting therapeutics could be improved by the molecular stratification of breast cancer patients.

miR-200c inhibits metastasis of breast cancer cells by targeting HMGB1

miR-200c has been shown to regulate the epithelial-mesenchymal transition (EMT) by inhibiting ZEB1 and ZEB2 expression in breast cancer cells. This study further examined the role of miR-200c in the invasion and metastasis of breast cancer that goes beyond the regulation on ZEB1 and ZEB2 expression. In this study, the bioinformatics software (miRanda) was used to predict the target gene of miR-200c and Renilla luciferase assay to verify the result. The metastatic breast cancer cells MDA-MB-231 were cultured and transfected with the miR-200c mimic or inhibitor. The expressions of miR-200c and HMGB1 were detected by RT-PCR and Western blotting, respectively. Transwell assay and wound healing assay were employed to examine the invasive and migrating ability of transfected cells. Target prediction and Renilla luciferase analysis revealed that HMGB1 was a putative target gene of miR-200c. After transfection of MDA-MB-231 cells with the miR-200c mimic or inhibitor, the expression of miR-200c was significantly increased or decreased when compared with cells transfected with the miR-200c mimic NC or inhibitor NC. Moreover, the expression of HMGB1 was reversely correlated with that of miR-200c in transfected cells. Tranwell assay showed that the number of invasive cells was significantly reduced in miR-200c mimic group when compared with miR-200c inhibitor group. It was also found that the migrating ability of cells transfected with miR-200c mimics was much lower than that of cells transfected with miR-200c inhibitors. It was suggested that miR-200c can suppress the invasion and migration of breast cancer cells by regulating the expression of HMGB1. miR-200c and HMGB1 may become useful biomarkers for progression of breast cancer and targets of gene therapy.SummarymiR-200c has been shown to regulate the epithelial-mesenchymal transition (EMT) by inhibiting ZEB1 and ZEB2 expression in breast cancer cells. This study further examined the role of miR-200c in the invasion and metastasis of breast cancer that goes beyond the regulation on ZEB1 and ZEB2 expression. In this study, the bioinformatics software (miRanda) was used to predict the target gene of miR-200c and Renilla luciferase assay to verify the result. The metastatic breast cancer cells MDA-MB-231 were cultured and transfected with the miR-200c mimic or inhibitor. The expressions of miR-200c and HMGB1 were detected by RT-PCR and Western blotting, respectively. Transwell assay and wound healing assay were employed to examine the invasive and migrating ability of transfected cells. Target prediction and Renilla luciferase analysis revealed that HMGB1 was a putative target gene of miR-200c. After transfection of MDA-MB-231 cells with the miR-200c mimic or inhibitor, the expression of miR-200c was significantly increased or decreased when compared with cells transfected with the miR-200c mimic NC or inhibitor NC. Moreover, the expression of HMGB1 was reversely correlated with that of miR-200c in transfected cells. Tranwell assay showed that the number of invasive cells was significantly reduced in miR-200c mimic group when compared with miR-200c inhibitor group. It was also found that the migrating ability of cells transfected with miR-200c mimics was much lower than that of cells transfected with miR-200c inhibitors. It was suggested that miR-200c can suppress the invasion and migration of breast cancer cells by regulating the expression of HMGB1. miR-200c and HMGB1 may become useful biomarkers for progression of breast cancer and targets of gene therapy.

Second-line pemetrexed versus docetaxel in Chinese patients with locally advanced or metastatic non-small cell lung cancer: A randomized, open-label study

INTRODUCTION This randomized, open-label study compared pemetrexed versus docetaxel as second-line therapy for Chinese patients with locally advanced or metastatic non-small cell lung cancer (NSCLC). The primary endpoint tested non-inferiority of overall survival (OS) on the combined data from these patients and those in the global registration trial. Data from patients in the current study only (Chinese patients) were the basis for the studys secondary objectives. METHODS Patients with stage IIIB/IV disease were randomized (1:1) to receive pemetrexed (500 mg/m(2); 107 randomized; 106 treated) or docetaxel (75 mg/m(2); 104 randomized; 102 treated) on Day 1 of each 21-day cycle. Treatment continued until progressive disease, unacceptable toxicity or patient/investigator decision. All efficacy and safety data were analyzed at the pre-specified study completion; supplementary OS analyses were performed later, after additional events had been recorded. RESULTS The primary endpoint of OS noninferiority of pemetrexed to docetaxel was not met, the lower CL was <50% and P>0.025 (efficacy retained=97.9% [95% CLs: 47.1, 141.9]; P=0.0276), in the combined population (pemetrexed: n=390, docetaxel: n=392). Supplementary values were 101.3% (95% CLs: 57.9, 148.8), P=0.0186. For the secondary objectives, assessed in the population from the current study (pemetrexed: n=107, docetaxel: n=104), median OS was 11.7 and 12.2 months for the pemetrexed and docetaxel arms, respectively (HR [95% CLs]: 1.14 [0.78, 1.68], P=0.492). Supplementary values were 11.4 and 11.5 months, respectively (HR [95% CLs]: 1.02 [0.74, 1.40], P=0.926). Median PFS values were 2.8 and 3.1 months (HR [95% CLs]: 1.05 [0.75, 1.46], P=0.770) and ORR values were 9.6% and 4.1% (odds ratio [95% CLs]: 2.50 [0.76, 8.25], P=0.133) for pemetrexed and docetaxel, respectively. Pemetrexed-treated patients had significantly fewer drug-related grade 3-4 adverse events (pemetrexed: 20.8%, docetaxel: 40.2%; P=0.003). Few drug-related serious adverse events were reported (pemetrexed: 5 patients, docetaxel: 8 patients). CONCLUSION The comparable efficacy and superior tolerability of pemetrexed compared with docetaxel in this study supports the use of single-agent, second-line pemetrexed for advanced non-squamous NSCLC in Chinese patients. ClinicalTrials.gov: NCT00391274.

A new rat model of bone cancer pain produced by rat breast cancer cells implantation of the shaft of femur at the third trochanter level.

Bone cancer pain remains one of the most challenging cancer pains to fully control. In order to clarify bone cancer pain mechanisms and examine treatments, animal models mimicking the human condition are required. In our model of Walker 256 tumor cells implantation of the shaft of femur at the third trochanter level, the anatomical structure is relatively simple and the drilled hole is vertical and in the cortical bone only 1–2 mm in depth without injury of the distal femur. Pain behaviors and tumor growth were observed for 21 days. And neurochemical changes were further investigated in this model. The results showed that cancer-bearing rats demonstrated a decreased limb use score from day 14, an increased spontaneous flinching and guarding times from day 7 and a decreased withdrawal threshold from day 6. The tumor infiltration of bone was monitored by MRI and further verified by histological examination. C-fos and the capsaicin receptor (TRPV1) positive neurons were more expressed in cancer-bearing rats and the substance P expression has no difference, suggesting that neurons were activated in the model. Our animal model demonstrated time-dependent tumor growth and pain behaviors and will be a novel animal model of bone cancer pain in the future.