Yinting Chen

The investigation of polymer-siRNA nanoparticle for gene therapy of gastric cancer in vitro

Small interfering RNA (siRNA) molecules have significant therapeutic promise for the genetic treatment of cancer. To overcome instability and low transfection efficiency, polyethylene glycol-polyethyleneimine (PEG-PEI) was synthesized and investigated as a non-viral carrier of siRNA targeting CD44v6 in gastric carcinoma cells. The size, surface charge using zeta potential, and morphology via scanning electron microscopy (SEM) of PEG-PEI/siRNA nanoparticles was characterized, and their cytotoxicity, transfection efficiency, and interaction with SGC7901 human gastric carcinoma cells was evaluated. The transfection efficiency of PEG-PEI/siRNA nanocomplexes was dependant on the charge ratio between amino groups of PEG-PEI and phosphate groups of siRNA (N/P) values, which reflected the molar ratio of PEG-PEI to siRNA during complex formation. The transfection efficiency of PEG-PEI/siRNA at N/P 15 was 72.53% ± 2.38%, which was higher than that observed using Lipofectamine 2000 and PEI as delivery carriers. Cytotoxicity of PEG-PEI was determined by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay and was obviously lower than that of PEI. Moreover, when N/P was below 15, PEG-PEI/siRNA was less toxic than Lipofectamine 2000/siRNA. RT-PCR (real time polymerase chain reaction) and Western blot analyses of CD44v6 expression demonstrated the gene silencing effect of PEG-PEI/siRNA at N/P 15. These data indicate that PEG-PEI may be a promising non-viral carrier for altering gene expression in the treatment of gastric cancer with many advantages, such as relatively high gene transfection efficiency and low cytotoxicity.

Higher sea fish intake is associated with greater bone mass and lower osteoporosis risk in postmenopausal Chinese women

SummaryWe examined the cross-sectional association of the intakes of different types of fishes with bone mass and osteoporosis risk in postmenopausal Chinese women. We found that higher intake of sea fish is independently associated with greater bone mass and lower osteoporosis risk among postmenopausal Chinese women.IntroductionFish contains many important nutrients that are beneficial on bone health, but limited data on the relationship between fish intake and bone health are available. We examined the association of the intakes of different types of fishes with bone mineral density (BMD) and bone mineral content (BMC) and osteoporosis risk.MethodsThis population-based cross-sectional study was conducted among 685 postmenopausal Chinese women. Habitual dietary intakes were assessed using food frequency questionnaire. BMD and BMC at the whole body, lumbar spine, and left hip were measured with dual-energy x-ray absorptiometry.ResultsAfter adjusting for the potential confounders, we observed dose-dependent relations between sea fish intake and BMDs, BMCs, and osteoporosis risk; the mean BMDs were 3.2–6.8% higher, and BMCs 5.1–9.4% higher in the top quintile groups (Q5) of sea fish intake than in the bottom quintile (Q1) at the whole body and hip sites (p < 0.05); the odds ratios (95% confidence interval (CI)) for osteoporosis (T-score < −2.5) in Q5 were 0.23 (0.08–0.66), 0.12 (0.03–0.59), and 0.06 (0.01–0.44) compared with those in Q1 at the whole body, total hip, and femur neck, respectively. No independent association between consumption of freshwater fish or shellfish and bone mass was observed.ConclusionHigher intake of sea fish is independently associated with greater bone mass and lower osteoporosis risk among postmenopausal Chinese women.

Pancreatic Cancer Epidemiology, Detection, and Management

PC (pancreatic cancer) is the fourth most common cause of death due to cancer worldwide. The incidence and mortality rates have been increasing year by year worldwide, and this review has analyzed the most recent incidence and mortality data for pancreatic cancer occurrence in China. Several possible risk factors have been discussed here, involving known established risk factors and novel possible risk factors. The development of this cancer is a stepwise progression through intraepithelial neoplasia to carcinoma. Though early and accurate diagnosis is promising based on a combination of recent techniques including tumor markers and imaging modalities, lacking early clinical symptoms makes the diagnosis late. Correct staging is critical because treatment is generally based on this parameter. Treatment options have improved throughout the last decades. However, surgical excision remains the primary therapy and efficacy of conventional chemoradiotherapy for PC is limited. Recently, some novel new therapies have been developed and will be applied in clinics soon. This review will provide an overview of pancreatic cancer, including an understanding of the developments and controversies.

Suppression of pancreatic tumor growth by targeted arsenic delivery with anti-CD44v6 single chain antibody conjugated nanoparticles.

Arsenic trioxide (As2O3) is a promising anticancer agent for solid tumors. However, the high toxicity to normal tissues resulting from the lack of tumor specificity remains a huge challenge in its systemic application. Targeted vectors enabling drug delivery to specific cancer cells bring about great potential for better therapeutic efficacy whereas low side effects in cancer treatments. Our previous work has demonstrated that the anti-CD44v6 single chain variable fragment (scFv(CD44v6)) screened out from the human phage-displayed scFv library possesses high specificity and affinity to membrane antigen CD44v6 over-expressing in a subset of epithelium-derived cancers, such as pancreatic, hepatocellular, colorectal and gastric cancers. Herein, a maleimide-functionalized amphiphilic diblock copolymer of poly (ethylene glycol) and poly (D, L-lactide) (mal-PEG-PDLLA) was synthesized and assembled to vesicles with arsenite ion (As) encapsulated in their cores (As-NPs). Conjugation of scFv(CD44v6) with mal-PEG-PDLLA (scFv-As-NPs) enabled more efficient delivery of As and exhibited higher cytotoxic activity than non-targeted ones (As-NPs) in human pancreatic cancer cells PANC-1. Furthermore, the targeted delivery of As induced more significant gene suppression in terms of the expression of anti-apoptotic Bcl-2 protein. Consequently, the expression level of cleaved caspase-3 which is a molecular indicator of cell apoptosis was remarkably elevated. In animal tests, scFv-As-NPs were found to greatly increase accumulation of drug in tumor site and potentiate the efficacy of As in inhibiting tumor growth owing to the enhanced cell apoptosis. These results imply that our tumor specific nanocarriers provide a highly efficient and safe platform for pancreatic cancer therapy.

Development of an MRI-visible nonviral vector for siRNA delivery targeting gastric cancer.

An antibody-directed nonviral vector, polyethylene glycol-grafted polyethylenimine functionalized with superparamagnetic iron oxide nanoparticles and a gastric cancer-associated CD44v6 single-chain variable fragment (scFvCD44v6,-PEG-g-PEI-SPION), was constructed as a gastric cancer-targeting and magnetic resonance imaging (MRI)-visible nanocarrier for small interfering RNA (siRNA) delivery. Biophysical characterization of PEG-g-PEI-SPION and scFvCD44v6-PEG-g-PEI-SPION was carried out, including siRNA condensation capacity, cell viability, and transfection efficiency. Both the targeting and nontargeting nanocarriers were effective for transferring siRNA in vitro. The cellular uptake and distribution of nanoparticles complexed with siRNA was analyzed by fluorescence imaging and immunofluorescent staining. Moreover, the gastric cancer-targeting effect was verified in vivo by MRI and histology analysis. These results indicate that scFvCD44v6-PEG-g-PEI-SPION is a promising nonviral vector for gastric cancer gene therapy and diagnosis.

Characterization of polyethylene glycol-grafted polyethylenimine and superparamagnetic iron oxide nanoparticles (PEG-g-PEI-SPION) as an MRI-visible vector for siRNA delivery in gastric cancer in vitro and in vivo.

BackgroundGene therapy is a promising therapeutic method but is severely hampered due to its lack of an ideal delivery system. Therefore, in this study, a nonviral and magnetic resonance imaging (MRI) visible vector, polyethylene glycol-grafted polyethylenimine and superparamagnetic iron oxide nanoparticles (PEG-g-PEI-SPION) was used as a nanocarrier for small interfering RNA (siRNA) delivery in gastric cancer.MethodsBiophysical characterization of PEG-g-PEI-SPION was systematically analyzed, including size, zeta potential, siRNA condensation capacity, cell viability, transfection efficiency, cellular uptake, and MRI-visible function in vivo. Besides, CD44 variant isoform 6 (CD44v6), a protein marker for metastatic behavior in gastric cancer, and was chose as the target gene to further analyze the siRNA delivery function of PEG-g-PEI-SPION.ResultsUnder comprehensive analysis, the appropriate N/P ratio of PEG-g-PEI-SPION/siRNA was 10,. and siRNA targeting at human CD44v6 (siCD44v6) transferred by PEG-g-PEI-SPION was effective at downregulating the CD44v6 expression of gastric carcinoma cell line SGC-7901 in vitro. Moreover, knockdown of CD44v6 impaired migrating and invasive abilities of SGC-7901 cells. Furthermore, PEG-g-PEI-SPION was a highly efficient contrast agent for MRI scan in vivo.ConclusionPEG-g-PEI-SPION was a promising nonviral vector with molecular image tracing capacity for cancer gene therapy. And CD44v6 was a potential target gene for the prevention and detection of metastatic behavior in gastric cancer.

Combination of siRNA-directed Kras oncogene silencing and arsenic-induced apoptosis using a nanomedicine strategy for the effective treatment of pancreatic cancer.

UNLABELLED The synergetic inhibitory effects on human pancreatic cancer by nanoparticle-mediated siRNA and arsenic therapy were investigated both in vitro and in vivo. Poly(ethylene glycol)-block-poly(L-lysine) were prepared to form siRNA-complexed polyplex and poly(ethylene glycol)-block-poly(DL-lactide) were prepared to form arsenic-encapsulated vesicle, respectively. Down-regulation of the mutant Kras gene by siRNA caused defective abilities of proliferation, clonal formation, migration, and invasion of pancreatic cancer cells, as well as cell cycle arrest at the G0/G1 phase, which substantially enhanced the apoptosis-inducing effect of arsenic administration. Consequently, co-administration of the two nanomedicines encapsulating siRNA or arsenic showed ideal tumor growth inhibition both in vitro and in vivo as a result of synergistic effect of the siRNA-directed Kras oncogene silencing and arsenic-induced cell apoptosis. These results suggest that the combination of mutant Kras gene silencing and arsenic therapy using nanoparticle-mediated delivery strategy is promising for pancreatic cancer treatment. FROM THE CLINICAL EDITOR Treatment of pancreatic cancer remains a major challenge. These authors demonstrate a method that combines a siRNA-based Kras silencing with arsenic delivery to pancreatic cancer cells using nanoparticles, resulting in enhanced apoptosis induction in the treated cells.

Effect of Preoperative Biliary Drainage on Complications Following Pancreatoduodenectomy: A Meta-Analysis

Abstract Preoperative biliary drainage (PBD) prior to pancreatoduodenectomy (PD) is still controversial; therefore, the aim of this study was to examine the impact of PBD on complications following PD. A meta-analysis was carried out for all relevant randomized controlled trials (RCTs), prospective and retrospective studies published from inception to March 2015 that compared PBD and non-PBD (immediate surgery) for the development of postoperative complications in PD patients. Pooled odds ratio (OR) and 95% confidence interval (CI) were estimated using fixed-effect analyses, or random-effects analyses if there was statistically significant heterogeneity (P < 0.05). Eight RCTs, 13 prospective studies, 20 retrospective studies, and 3 Chinese local retrospective studies with 6286 patients were included in this study. In a pooled analysis, there were no significant differences between PBD and non-PBD group in the risks of mortality, morbidity, intra-abdominal abscess, sepsis, hemorrhage, pancreatic leakage, and biliary leakage. However, subgroup analysis of RCTs yielded a trend toward reduced risk of morbidity in PBD group (OR 0.48, CI 0.24 to 0.97; P = 0.04). Compared with non-PBD, PBD was associated with significant increase in the risk of infectious complication (OR 1.52, CI 1.07 to 2.17; P = 0.02), wound infection (OR 2.09, CI 1.39 to 3.13; P = 0.0004), and delayed gastric emptying (DGE) (OR 1.37, CI 1.08 to 1.73; P = 0.009). This meta-analysis suggests that biliary drainage before PD increased postoperative infectious complication, wound infection, and DGE. In light of the results of the study, PBD probably should not be routinely carried out in PD patients.

Co‐delivery of microRNA‐21 antisense oligonucleotides and gemcitabine using nanomedicine for pancreatic cancer therapy

Tumor metastasis occurs naturally in pancreatic cancer, and the efficacy of chemotherapy is usually poor. Precision medicine, combining downregulation of target genes with chemotherapy drugs, is expected to improve therapeutic effects. Therefore, we developed a combined therapy of microRNA‐21 antisense oligonucleotides (ASO‐miR‐21) and gemcitabine (Gem) using a targeted co‐delivery nanoparticle (NP) carrier and investigated the synergistic inhibitory effects on pancreatic cancer cells metastasis and growth. Polyethylene glycol–polyethylenimine–magnetic iron oxide NPs were used to co‐deliver ASO‐miR‐21 and Gem. An anti‐CD44v6 single‐chain variable fragment (scFvCD44v6) was used to coat the particles to obtain active and targeted delivery. Our results showed that the downregulation of the oncogenic miR‐21 by ASO resulted in upregulation of the tumor‐suppressor genes PDCD4 and PTEN and the suppression of epithelial–mesenchymal transition, which inhibited the proliferation and induced the clonal formation, migration, and invasion of pancreatic cancer cells in vitro. The co‐delivery of ASO‐miR‐21 and Gem induced more cell apoptosis and inhibited the growth of pancreatic cancer cells to a greater extent than single ASO‐miR‐21 or Gem treatment in vitro. In animal tests, more scFvCD44v6‐PEG‐polyethylenimine/ASO‐magnetic iron oxide NP/Gem accumulated at the tumor site than non‐targeted NPs and induced a potent inhibition of tumor proliferation and metastasis. Magnetic resonance imaging was used to observed tumor homing of NPs. These results imply that the combination of miR‐21 gene silencing and Gem therapy using an scFv‐functionalized NP carrier exerted synergistic antitumor effects on pancreatic cancer cells, which is a promising strategy for pancreatic cancer therapy.

Perineural Invasion and TAMs in Pancreatic Ductal Adenocarcinomas: Review of the Original Pathology Reports Using Immunohistochemical Enhancement and Relationships with Clinicopathological Features.

Objectives: Tumor-associated macrophages (TAMs) are thought to be involved in the perineural invasion (PNI) process and to be associated with poor prognoses. The associations between TAMs, PNI, and clinicopathological features in pancreatic ductal adenocarcinomas (PDAs) remain to be elucidated. Methods: Fifty-nine PDA patients who had undergone pancreaticoduodenectomy were retrospectively examined. The PNI statuses and TAMs were reviewed following H&E staining and S-100, CD68, and CD163 immunohistochemical staining. The relationships between PNI, TAMs, and overall survival and various clinical and histopathologic factors were investigated. Results: PNI was identified in 83% (49/59) of the cases, the TAM density of the PNI+ group was greater than that of the PNI- group, and the infiltrating TAMs around the nerves that were invaded by cancer were much more numerous than those around the nerves without cancer cell invasion. The incidences of PNI, lymph node metastasis, high serum CA19-9 level, cancers in the body/tail, and advanced pathological stage were associated with shorter OSs. In the PNI+ group, lymph node metastasis and high levels of TAM infiltration were associated with worse prognoses. Conclusions: TAMs might enhance PNI, and the incidence of PNI was associated with poor prognosis. PNI+ status and high levels of TAM infiltration further worsen the prognosis. Therapies targeting TAMs might represent auxiliary and preventive treatment for PNI in PDA patients.