Gelatinases-stimuli nanoparticles encapsulating 5-fluorouridine and 5-aza-2'-deoxycytidine enhance the sensitivity of gastric cancer cells to chemical therapeutics.

Aberrant methylation of the transcription factor AP-2 epsilon (TFAP2E) has been attributed to 5-fluorouridine (5-FU) sensitivity. 5-Aza-2'-deoxycytidine (DAC), an epigenetic drug that inhibits DNA methylation, is able to cause reactive expression of TFAP2E by demethylating activity. This property might be useful in enhancing the sensitivity of cancer cells to 5-FU. However, the effect of DAC is transient because of its instability. Here, we report the use of intelligent gelatinases-stimuli nanoparticles (NPs) to coencapsulate and deliver DAC and 5-FU to gastric cancer (GC) cells. The results showed that NPs encapsulating DAC, 5-FU, or both could be effectively internalized by GC cells. Furthermore, we found that the NPs enhanced the stability of DAC, resulting in improved re-expression of TFAP2E. Thus, the incorporation of DAC into NPs significantly enhanced the sensitivity of GC cells to 5-FU by inhibiting cell growth rate and inducing cell apoptosis. In conclusion, the results of this study clearly demonstrated that the gelatinases-stimuli NPs are an efficient means to simultaneously deliver epigenetic and chemotherapeutic drugs that may effectively inhibit cancer cell proliferation.

Enhancement of radiotherapy efficacy by miR-200c-loaded gelatinase-stimuli PEG-Pep-PCL nanoparticles in gastric cancer cells.

Radiotherapy is the main locoregional control modality for many types of unresectable tumors, including gastric cancer. However, many patients fail radiotherapy due to intrinsic radioresistance of cancer cells, which has been found to be strongly associated with cancer stem cell (CSC)-like properties. In this study, we developed a nanoparticle formulation to deliver miR-200c, which is reported to inhibit CSC-like properties, and then evaluated its potential activity as a radiosensitizer. miR-200c nanoparticles significantly augmented radiosensitivity in three gastric cancer cell lines (sensitization enhancement ratio 1.13-1.25), but only slightly in GES-1 cells (1.06). In addition to radioenhancement, miR-200c nanoparticles reduced the expression of CD44, a putative CSC marker, and the percentage of CD44(+) BGC823 cells. Meanwhile, other CSC-like properties, including invasiveness and resistance to apoptosis, could be suppressed by miR-200c nanoparticles. CSC-associated radioresistance mechanisms, involving reactive oxygen species levels and DNA repair capacity, were also attenuated. We have demonstrated that miR-200c nanoparticles are an effective radiosensitizer in gastric cancer cells and induce little radiosensitization in normal cells, which suggests that they are as a promising candidate for further preclinical and clinical evaluation.

TAZ is highly expressed in gastric signet ring cell carcinoma.

Transcriptional coactivator with PDZ-binding motif (TAZ) is known to bind to a variety of transcription factors to control cell differentiation and organ development. We examined TAZ protein levels in 146 stage II-IV gastric cancer using immunohistochemistry (IHC), while TAZ mRNA was confirmed by quantitative reverse-transcription polymerase chain reaction (QRT-PCR) in 84 samples with enough tissue. TAZ protein expression was positive in 113 out of 146 (77.4%) gastric cancer samples. In parallel, TAZ mRNA expression was successfully detected in 81 of the 84 (96.4%) samples. Protein levels of TAZ were positively correlated with its mRNA levels (P = 0.018). High expression of TAZ protein was observed with higher percentage in gastric cancer samples with histology of signet ring cell carcinoma (SRCC) than adenocarcinoma (85.7% versus 60.2%, P = 0.001). Similarly, TAZ mRNA level was higher in SRCC than in adenocarcinoma (P = 0.003). When correlated with survival, the median overall survival (OS) is 14 months (95% CI: 12.2-15.8 months) in all patients. There was no significant association between survival and other clinical characteristics or TAZ expression levels. Our results show that TAZ is highly expressed in SRCC. TAZ might be considered as a target for the treatment of gastric SRCC in future.

Carboxybetaine methacrylate-modified nylon surface for circulating tumor cell capture.

Conventional in vitro circulating tumor cell (CTC) detection methods are always limited by blood sample volume because of the requirement of a large amount of blood. The aim of this study was to overcome the limitation by designing and making an in vivo CTC capture device. In this study, we designed and prepared a kind of proper material to serve the purpose of intervention. A method employing 3-aminopropyltriethoxysilane (γ-APS) as the coupling reagent to graft carboxybetaine methacrylate (CBMA) and to immobilize an anti-epithelial cell adhesion molecular (EpCAM) antibody on Nylon was developed. The results of X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy proved the successful graft of γ-APS and CBMA to Nylon. Furthermore, the predicted improvement in the biocompatibilities of our modified Nylon was confirmed by water contact angle measurement, bovine serum albumin adhesion, platelet adhesion, plasma recalcification time determination, and cytotoxicity tests. The tumor cells adhesion experiment revealed that Nylon with the antibody immobilized on it had an affinity for EpCAM positive tumor cells higher than that of pristine Nylon. Additionally, the capture ability of the CTCs was demonstrated in a nude mouse tumor model using the interventional device made of the modified Nylon wire. The positive results suggest that CBMA-grafted and anti-EpCAM antibody-immobilized Nylon is a promising new material for in vivo CTC capture devices.

Enhancement of radiotherapy efficacy by docetaxel-loaded gelatinase-stimuli PEG-Pep-PCL nanoparticles in gastric cancer.

Docetaxel (DOC) is widely used as radiosensitizer in various tumors, including gastric cancer (GC), but its therapeutic effect remains to be improved. In this study, using docetaxel-loaded nanoparticles (DOC-NPs) based on gelatinase-stimuli strategy, we compared their radioenhancement efficacy with docetaxel in GC. Compared with DOC, radiosensitization of DOC-NPs was improved significantly (sensitization enhancement ratio increased 1.09-fold to 1.24-fold, P<0.01) in all three gelatinase overexpressing GC cells, while increased slightly (1.02-fold, P=0.38) in gelatinase deficient normal gastric mucosa cells. The improved radiosensitization efficacy was associated with enhanced G2/M arrest, increased reactive oxygen species (ROS), more effective DSBs and promoted apoptosis. More importantly, the radiosensitization efficacy of DOC-NPs (estimated as ''very active'') was more prominent than DOC (estimated as ''moderately active'') by intravenous injection in xenograft. In conclusion, DOC-NPs are highly selective radiosensitizers in gelatinase over-expressing tumors, and more effective than DOC. By manipulating the common microenvironment difference between tumor and normal tissue, gelatinase-mediated nanoscale delivery system serves as a potential strategy possessing both universality and selectivity for radiosensitizers.

Facile preparation of paclitaxel loaded silk fibroin nanoparticles for enhanced antitumor efficacy by locoregional drug delivery.

Non-toxic, safe materials and preparation methods are among the most important factors when designing nanoparticles (NPs) for future clinical application. Here we report a novel and facile method encapsulating anticancer drug paclitaxel (PTX) into silk fibroin (SF), a biocompatible and biodegradable natural polymer, without adding any toxic organic solvents, surfactants or other toxic agents. The paclitaxel loaded silk fibroin nanoparticles (PTX-SF-NPs) with a diameter of 130 nm were formed in an aqueous solution at room temperature by self-assembling of SF protein, which demonstrated mainly silk I conformation in the NPs. In cellular uptake experiments, coumarin-6 loaded SF NPs were taken up efficiently by two human gastric cancer cell lines BGC-823 and SGC-7901. In vitro cytotoxicity studies demonstrated that PTX kept its pharmacological activity when incorporating into PTX-SF-NPs, while SF showed no cytotoxicity to cells. The in vivo antitumor effects of PTX-SF-NPs were evaluated on gastric cancer nude mice exnograft model. We found that locoregional delivery of PTX-SF-NPs demonstrated superior antitumor efficacy by delaying tumor growth and reducing tumor weights compared with systemic administration. Furthermore, the organs of mice in NP treated groups didn't show obvious toxicity, indicating the in vivo safety of SF NPs. These results suggest that SF NPs are promising drug delivery carriers, and locoregional delivery of SF NPs could be a potential future clinical cancer treatment regimen.

SULF2 methylation is associated with in vitro cisplatin sensitivity and clinical efficacy for gastric cancer patients treated with a modified FOLFOX regimen.

OBJECTIVE: Biomarkers capable of discriminating the patients who are likely to respond to certain chemotherapeutic agents could improve the clinical efficiency. The sulfatases(SULFs) play a critical role in the pathogenesis of a variety of human cancers. Here, we focused our investigation on the prognostic and predictive impact of SULF2 methylation in gastric cancer. METHODS: Promoter CpG island methylation of SULF2 was analyzed in 100 gastric cancer samples. The in vitro sensitivity to cisplatin, docetaxel, gemcitabine, irinotecan and pemetrexed were determined by histoculture drug response assay(HDRA). Additionally, 56 gastric cancer patients treated with a modified FOLFOX regimen(biweekly oxaliplatin plus 5-FU and folinic acid) were retrospectively analyzed to further evaluate the prognostic and predictive impact of SULF2 methylation in gastric cancer. RESULTS: Methylated SULF2(SULF2M) was detected in 28 patients, while the remaining 72 patients showed unmethylated SULF2(SULF2U, methylation rate: 28%). Samples with SULF2U were more sensitive to cisplatin than those with SULF2M(inhibition rate: 48.80% vs. 38.15%, P = 0.02), while samples with SULF2M were more sensitive to irinotecan than SULF2U(inhibition rate: 53.61% vs. 40.92%, P = 0.01). There were no association between SULF2 methylation and in vitro sensitivity to docetaxel, gemcitabine and pemetrexed. SULF2 methylation was found to have a significant association with cisplatin efficacy(SULF2M: 57.14%, SULF2U: 80.56%, P = 0.02) and irinotecan efficacy(SULF2M: 89.29%, SULF2U: 62.50%, P = 0.01). Among the 56 patients receiving the modified FOLFOX regimen, a significant association was observed between survival and SULF2 methylation status(SULF2M: 309 days, 95% CI = 236 to 382 days; SULF2U: 481 days, 95% CI = 418 to 490 days; P = 0.02). Multivariate analysis revealed that SULF2 methylation was an independent prognostic factor of overall survival in gastric cancer patients treated with platinum-based chemotherapy. CONCLUSION: SULF2 methylation is negatively associated with cisplatin sensitivity in vitro. SULF2 methylation may be a novel prognostic biomarker for gastric cancer patients treated with platinum-based chemotherapy.

Synergistic anticancer effects of polyphyllin I and evodiamine on freshly-removed human gastric tumors.

OBJECTIVE: The present study was designed to examine the anticancer effect of Traditional Chinese Medicine of polyphyllin I (PPI) and evodiamine (EVO) on freshly-removed gastric tumor tissues. METHODS: Sixty freshly-removed gastric tumor tissues were collected. Their sensitivity to PPI, EVO, platinum (Pt), 5-FU, irinotecan (CPT-11) were determined by histoculture drug response assay (HDRA). Those samples were also formalin-fixed and paraffin-embedded, which were used to examine the mRNA expression levels of aprataxin(APTX), excision repair cross-complementing 1(ERCC1), thymidylate synthase(TS) and topoisomerase I(TOPO1) by quantitative RT-PCR. The association of the gene expression levels and in vitro sensitivity were analyzed. RESULTS: PPI, EVO, Pt, 5-FU and CPT-11 had anticancer effects on the freshly-removed gastric tumor tissues with average inhibition rates of 20.64%±14.25% for PPI, 21.14%±13.43% for EVO, 50.57%±22.37% for Pt, 53.54%±22.03% for 5-FU, and 39.33%±24.79% for CPT-11, respectively. Combination of PPI and Pt, EVO and Pt, EVO and 5-FU had higher inhibition rates than any single drug of them (P<0.001, P = 0.028, P = 0.017, respectively). The mRNA expression levels of ERCC1 were correlated with Pt sensitivity (rho = -0.645, P<0.001); the mRNA expression levels of TS were correlated with 5-FU sensitivity (rho = -0.803, P<0.001). There were also weak but significant correlations between APTX mRNA expression levels and CPT-11 sensitivity (rho = -0.376, P = 0.017) or EVO sensitivity (rho = -0.322, P = 0.036). ERCC1 mRNA expression levels was markedly suppressed by the presentation of PPI (P = 0.001) and slightly suppressed by the presentation of EVO (P = 0.04); whereas, TS mRNA expression levels was markedly decreased by the presentation of EVO (P = 0.017) and slightly decreased by the presentation of PPI (P = 0.047). CONCLUSION: PPI and EVO both could inhibit the activity of freshly-removed gastric tumor, and they could enhance the anticancer effect of Pt and 5-FU by reducing the mRNA expression levels of ERCC1 and TS.

A three-gene signature as potential predictive biomarker for irinotecan sensitivity in gastric cancer.

OBJECTIVE: Personalized chemotherapy based on molecular biomarkers can maximize anticancer efficiency. We aim to investigate predictive biomarkers capable of predicting response to irinotecan-based treatment in gastric cancer. METHODS: We examined gene expression of APTX, BRCA1, ERCC1, ISG15, Topo1 and methylation of SULF2 in formalin-fixed paraffin-embedded gastric cancer tissues from 175 patients and evaluated the association between gene expression levels or methylation status and in vitro sensitivity to irinotecan. We used multiple linear regression analysis to develop a gene-expression model to predict irinotecan sensitivity in gastric cancer and validated this model in vitro and vivo. RESULTS: Gene expression levels of APTX, BRCA1 and ERCC1 were significantly lower in irinotecan-sensitive gastric cancer samples than those irinotecan-resistant samples (P<0.001 for all genes), while ISG15 (P=0.047) and Topo1 (P=0.002) were significantly higher. Based on those genes, a three-gene signature were established, which was calculated as follows: Index =0.488 - 0.020× expression level of APTX + 0.015× expression level of Topo1 - 0.011 × expression level of BRCA1. The three-gene signature was significantly associated with irinotecan sensitivity (rho=0.71, P<0.001). The sensitivity and specificity for the prediction of irinotecan sensitivity based on the three-gene signature reached 73% and 86%, respectively. In another independent testing set, the irinotecan inhibition rates in gastric samples with sensitive-signature were much higher than those with resistant-signature (65% vs. 22%, P<0.001). Irinotecan therapy with 20 mg/kg per week to immunodeficient mice carrying xenografts with sensitive-signature dramatically arrested the growth of tumors (P<0.001), but had no effect on mice carrying xenografts with resistant-signature. CONCLUSIONS: The three-gene signature established herein is a potential predictive biomarker for irinotecan sensitivity in gastric cancer.