Yuebo Yang

Improved therapeutic effect of folate-decorated PLGA–PEG nanoparticles for endometrial carcinoma

Folate (FOL) mediated poly-lactide-co-glycolide-polyethylene glycol nanoparticles (FOL-PEG-PLGA NPs) bearing paclitaxel (PTX) were prepared for the effective delivery of drug to endometrial carcinoma. The average size, zeta potential and encapsulation efficiency of FOL-targeted NPs were found to be around 220 nm, -30.43 mV and 95.6%. Cellular uptake was observed. The accumulation of FOL-targeted NPs depends on dual effects of passive and active targeting. The FOL-targeted PTX NPs showed a greater cytotoxicity against HEC-1A cancer cells in vitro and in vivo, which might be induced by apoptosis. H&E staining did not showed apparent tissue damage to liver and kidney of the mice after injecting NPs intravenously. These results suggest that the novel FOL-PEG-PLGA NPs could be a potential delivery system with excellent therapeutic efficacy for targeting the drugs to cancer cells.

ABT-737 Induces Bim Expression via JNK Signaling Pathway and Its Effect on the Radiation Sensitivity of HeLa Cells

ABT-737 is a BH3 mimetic small molecule inhibitor that can effectively inhibit the activity of antiapoptotic Bcl-2 family proteins including Bcl2, Bcl-xL and Bcl-w, and further enhances the effect of apoptosis by activating the proapoptotic proteins (t-Bid, Bad, Bim). In this study, we demonstrate that ABT-737 improved the radiation sensitivity of cervical cancer HeLa cells and thereby provoked cell apoptosis. Our results show that ABT-737 inhibited HeLa cell proliferation and activated JNK and its downstream target c-Jun, which caused the up-regulation of Bim expression. Blockade of JNK/c-Jun signaling pathway resulted in significant down-regulation of ABT-737-induced Bim mRNA and protein expression level. Also, ABT-737 could evoke the Bim promoter activity, and enhance the radiation sensitivity of HeLa cells via JNK/c-Jun and Bim signaling pathway. Our data imply that combination of ABT-737 and conventional radiation therapy might represent a highly effective therapeutic approach for future treatment of cervical cancer.

CHFR suppression by hypermethylation sensitizes endometrial cancer cells to paclitaxel.

Objective: Impairment of a cell cycle checkpoint is often associated with sensitivity to chemotherapeutic drugs. Here, we studied the correlations between the checkpoint with forkhead-associated and ring finger (CHFR) gene expression and responses to paclitaxel in endometrial cancer cells. Methods: We cultured 6 endometrial cancer cell lines exposed to paclitaxel, studied the cell cytotoxicity, cell cycle distribution, CHFR expression, and methylation status before and after a demethylation agent (5-aza) treatment. CHFR was silenced by small interfering RNA (siRNA). Then we examined tumor growth and CHFR expression with paclitaxel alone or combined with 5-aza pretreatment in vivo. Results: We found that HEC-1B, RL-952, and AN3CA cells were sensitive to paclitaxel. Moreover, CHFR was weakly expressed in these cells, whereas paclitaxel-resistant cells (ISH, HEC-1A, and KLE) had high CHFR expression. Then we found that restored expression of CHFR by demethylation decreased the sensitivity to paclitaxel in AN3CA cells. In addition, cells with CHFR demethylation resulted in G2/M phase arrest that induced to paclitaxel resistance. These results were confirmed again in small interfering RNA-transfected HEC-1A cells. Furthermore, in nude mice model, restored expression of CHFR by demethylation inhibited tumor growth and decreased sensitivity to paclitaxel. Conclusion: Our data suggest that CHFR suppression regulated by hypermethylation may sensitize endometrial cancer cells to paclitaxel, and CHFR may be a promising marker to predict the response of endometrial cancer to paclitaxel.

EGFR- and AKT-mediated reduction in PTEN expression contributes to tyrphostin resistance and is reversed by mTOR inhibition in endometrial cancer cells.

Loss or mutation of the PTEN (phosphatase and tensin homologue deleted on chromosome 10) gene is associated with resistance to epidermal growth factor receptor (EGFR) inhibitors. However, the mechanism underlying remains elusive. In this study, we aimed to explore whether sensitivity to the EGFR tyrosine kinase inhibitor (TKI) is affected by PTEN status in endometrial cancer cells. PTEN siRNA and the PTEN gene were transfected into HEC-1A and Ishikawa endometrial cancer cells using lentiviral vectors. Cells were treated under various concentrations of RG14620 and rapamycin, which are EGFR and mammalian target of rapamycin (mTOR) inhibitors, respectively. The IC50 of RG16420 was determined by using the MTT method. Cell apoptosis and the cell cycle were studied, and activation of EGFR, AKT, and p70S6 were detected by Western blot analysis. Loss of PTEN promoted cell proliferation and led to significant increases in the levels of EGFR, phospho-EGFR, AKT, phospho-AKT, and phospho-mTOR proteins. Ishikawa and HEC-1APTENkd cells that displayed loss and inactivation of PTEN function were resistant to RG14620. HEC-1A and IshikawaPTEN cells with intact PTEN were sensitive to RG14620. The combination of two inhibitors was more effective than both monotherapies, particularly in carcinoma cells with PTEN dysfunction. Decreased phospho-EGFR protein expression was observed in all cell lines that were sensitive to RG14620. Decreased phospho-AKT and phospho-p70S6 protein expression was observed in PTEN-intact cells that were sensitive to RG14620. PTEN loss results in resistance to EGFR TKI, which was reversed by PTEN reintroduction or mTOR inhibitor treatment. The combined treatment of EGFR TKI and the mTOR inhibitor provided a synergistic effect by promoting cell death in PTEN-deficient and PTEN-intact endometrial cancer cells, particularly in PTEN-deficient carcinoma cells with up-regulated EGFR activation.

Identification of five serum protein markers for detection of ovarian cancer by antibody arrays.

Background Protein and antibody arrays have emerged as a promising technology to study protein expression and protein function in a high-throughput manner. These arrays also represent a new opportunity to profile protein expression levels in cancer patients’ samples and to identify useful biosignatures for clinical diagnosis, disease classification, prediction, drug development and patient care. We applied antibody arrays to discover a panel of proteins which may serve as biomarkers to distinguish between patients with ovarian cancer and normal controls. Methodology/Principal Findings Using a case-control study design of 34 ovarian cancer patients and 53 age-matched healthy controls, we profiled the expression levels of 174 proteins using antibody array technology and determined the CA125 level using ELISA. The expression levels of those proteins were analyzed using 3 discriminant methods, including artificial neural network, classification tree and split-point score analysis. A panel of 5 serum protein markers (MSP-alpha, TIMP-4, PDGF-R alpha, and OPG and CA125) was identified, which could effectively detect ovarian cancer with high specificity (95%) and high sensitivity (100%), with AUC =0.98, while CA125 alone had an AUC of 0.87. Conclusions/Significance Our pilot study has shown the promising set of 5 serum markers for ovarian cancer detection.

Inhibitory effect of siRNA targeting IGF-1R on endometrial carcinoma.

The type-1 insulin-like growth factor receptor (IGF-1R) is one member of tyrosine protein kinase receptor family. It is a causal factor for tumor initiation, development and frequently overactivated in a variety of human malignancies, including endometrial carcinoma. To investigate its possibility as a therapeutic target for endometrial carcinoma, we adopted RNA interference technology to down-regulate IGF-1R expression in endometrial carcinoma and analyzed its apoptosis inductive effect and tumorigenicity in vivo. Results showed that RNAi mediated down-regulation of IGF-1R expression in endometrial carcinoma significantly induced apoptosis, reduced downstream protein phosphorylation and decreased tumorigenicity in vivo accompanied with lower proliferation index in tumor tissue, Which implied the therapeutic potential of RNAi in the treatment of endometrial carcinoma by targeting IGF-1R and IGF-1R may be a potential therapeutic target for human endometrial carcinoma.

Down-regulation of IGF-1R expression inhibits growth and enhances chemosensitivity of endometrial carcinoma in vitro

The type-1 insulin-like growth factor receptor (IGF-1R) is over-expressed by endometrial carcinoma, level of IGF-1R has been correlated with tumor progression, and high IGF-1R expression has been found to be an important prognostic factor. In the study, we used lentivirus-mediated shRNA targeting IGF-1R to silence its expression, then assessed the effect of down-regulation of this receptor on cell growth and chemosensitivity to cisplatin. Lentivirus-mediate shRNA was designed and transfected to the endometrial carcinoma HEC-1B cell. The IGF-1R mRNA and related protein expression, cell proliferation ability, cell apoptosis, and cell cycle change were detected. Cell proliferation inhibition rates, cell apoptosis, and level of cleaved caspase-9 were measured in various concentrations of cisplatin. The mRNA and protein level of IGF-1R, and the phosphorylated protein p-Akt, p-Erk were all suppressed after transfection. Cell proliferation was inhibited in successive five days after transfection, the highest inhibition rate was 43.28xa0±xa03.55% on day 5. After transfection, 24.96xa0±xa01.05% cells were in G2/M phase, and cell apoptotic rate increased from 10.66xa0±xa00.08 to 19.92xa0±xa01.34%. In various concentrations of cisplatin, transfected cells proliferation was significantly inhibited which made the IC50 value drop from 21.85xa0uM to 10.58xa0uM. Incubation with different concentrations of cisplatin for 48xa0h, cells apoptotic rate increased to 41.92xa0±xa02.5, 31.13xa0±xa02.76, 22.21xa0±xa04.63%, respectively, which was accompanied with increased cleaved caspase-9 expression. Lentivirus-mediated shRNA targeting IGF-1R has the potential to develop as a clinical treatment method in advanced and chemoresistant endometrial carcinoma.

Differential sensitivity of human endometrial carcinoma cells with different PTEN expression to mitogen-activated protein kinase signaling inhibits and implications for therapy

PurposePrior studies in different tumor models have shown that, under conditions of PTEN deficiency, the mitogen-activated protein kinase (MAPK) signaling pathway appear to play a major role in the tumor cell’s proliferative and survival pathway, and that pharmacological inhibition of this pathway results in tumor growth inhibition. This study aimed to explore whether sensitivity to p38MAPK inhibitors are specifically due to status of PTEN in endometrial cancer cells.MethodsWe developed a series of endometrial cancer cell lines with different PTEN expressions (Ishikawa, RL-952, HEC-1B and HEC-1A cells) or introduced the wild-type PTEN and PTEN-siRNA in four endometrial cancer cells to change its PTEN expression with a p38MAPK inhibitor, SB203580 for 2xa0days. Cell proliferation, cell apoptosis, and cell cycle distribution were studied, and activation of AKT, ATF-2, and p38MAPK was examined by Western blotting.ResultsIn cultivated PTEN-deficient endometrial cancer cells, in addition to an activation of AKT, a phosphorylation of p38MAPK and ATF-2 was evident, while PTEN-positive endometrial cancer cells lacked AKT activation but revealed a reduced expression of p-p38MAPK and p-ATF-2. These PTEN-deficient endometrial cancer cells demonstrated an increased sensitivity to the anti-proliferative effects induced by SB203580 compared with the PTEN-positive endometrial cancer cells, which corresponded to alterations in cell cycle response and cell apoptosis.ConclusionsPTEN-deficient endometrial cancer cells exhibit higher p38MAPK activity, and genetic studies demonstrate that p38MAPK functions dependently of AKT. Furthermore, PTEN loss sensitizes cells to p38MAPK inhibition in endometrial carcinoma cells. These findings indicate that inhibitors of p38MAPK have the potential to be effective in the treatment of endometrial cancer patients with PTEN-deficient tumors and should be evaluated in this setting.

Successful conservative management with methotrexate and mifepristone of cervical pregnancy.

This study investigated possible effective treatments for cervical pregnancy, a rare form of ectopic pregnancy. The clinical records of 11 cases of ectopic pregnancy admitted to the Third Affiliated Hospital of Sun Yat-sen University from 1998 to 2010 were analyzed. All patients were treated with intermuscular injection of methotrexate (MTX, 50 mg), and oral mifepristone (25 mg, bid). All cases were successfully cured by conservative treatments using methotrexate plus mifepristone. Cervical pregnancy is a contributive factor to mutiple abortions and curettages. Methotrexate plus mifepristone, curettage through hysteroscopy and intracervical obturation with gauze are effective treatments of cervical pregnancy without the need for surgical intervention.

MicroRNA-433 inhibits cervical cancer progression by directly targeting metadherin to regulate the AKT and β-catenin signalling pathways

Cervical cancer is one of the most common female malignancies worldwide. Emerging data have shown that microRNAs (miRNAs) play significant roles in various human cancers, including cervical cancer. Aberrantly expressed miRNAs in cervical cancer contribute to tumour occurrence and development as either tumour suppressors or promoters. Research suggests that miRNA-433 (miR-433) possibly plays an important role in the development of various cancer types. However, no study has explored the expression patterns, roles and underlying mechanisms of miR-433 in cervical cancer. In the present study, we demonstrated significant downregulation of miR-433 in cervical cancer tissues and cell lines. Low miR-433 expression was found to significantly correlate with patient characteristics including tumour size, International Federation of Gynecology and Obstetrics stage, lymph node and distant metastases. Functional studies showed that restoration of miR-433 inhibited cell proliferation and invasion and increased apoptosis in cervical cancer cells. Metadherin (MTDH) was also validated as a direct target gene of miR-433. MTDH mRNA expression was upregulated in cervical cancer tissues and was inversely correlated with miR-433 expression. MTDH knockdown showed similar tumour-suppressive roles as miR-433 overexpression in regards to cervical cancer cell proliferation, invasion and apoptosis. Rescue experiments revealed that MTDH overexpression markedly reversed the effects of miR-433 overexpression in regards to proliferation, invasion and apoptosis of cervical cancer cells. Further investigations revealed that miR-433 inactivated AKT and β-catenin pathways in cervical cancer. Collectively, these findings indicate the essential roles of miR-433 in suppressing cervical cancer progression and suggest its potential as a therapeutic target for the treatment of cervical cancer.