Correlation of epidermal growth factor receptor overexpression with increased epidermal growth factor receptor gene copy number in esophageal squamous cell carcinomas

Background  Esophageal squamous cell carcinoma (ESCC) is one of the most frequent malignancies in China and epidermal growth factor receptor (EGFR) is widely distributed in human epithelial cell membrane. The aim of this study was to investigate the protein overexpression and gene copy number of EGFR in ESCC, and help to identify patients who may benefit from EGFR targeted therapies.  

Methods  Immunohistochemistry (IHC) was performed to analyze the expression of EGFR in 105 cases of ESCC, 16 cases of squamous epithelial atypical hyperplasia, and 11 cases of normal esophageal tissue. Fluorescence in situ hybridization (FISH) was performed to analyze the gene copy number in 80 cases of ESCC, eight cases of squamous epithelial atypical hyperplasia, and eight samples of normal esophageal tissue.

Results  The IHC-positive rates of EGFR in 105 cases of ESCC, 16 cases of squamous epithelial atypical hyperplasia, and 11 normal esophageal tissues were 97% (102/105), 44% (7/16), and 18% (2/11) respectively. The difference in the expression of EGFR among different esophageal tissue groups had statistically significance (P <0.05). Among the 105 cases of ESCC, overexpression of EGFR was found in 90 cases (86%), of which 55 cases scored 3+ for EGFR staining and 35 cases scored 2+. In ESCC, the expression of EGFR was significantly correlated with depth of invasion and TNM stage (P <0.05), but not with other parameters. The FISH-positive rates of EGFR in 80 cases of ESCC, the eight cases of squamous epithelial atypical hyperplasia, and eight samples of normal esophageal tissue were 31.3% (25/80), 0 (0/8) and 0 (0/8) respectively. In ESCC, EGFR gene amplification was found in 17 (21%) cases, high polysomy in 8 (10%) cases, disomy in 34 cases, low trisomy in 17 cases, and high trisomy in four cases. EGFR FISH-positive was significantly correlated with depth of invasion and lymph node metastasis (P <0.05). EGFR FISH-positive was significantly associated with overexpression of EGFR.

Conclusion  Protein overexpression and/or increased gene copy number of EGFR is common in ESCC, and EGFR targeted therapy may be appropriate for ESCC patients.

     

miR-30b and miR-30c expression predicted response to tyrosine kinase inhibitors as first line treatment in non-small cell lung cancer

Background Aberrantly expressed microRNAs are a hallmark of cancer,and microRNA expression profiling is associated with tumor progression and response to chemotherapy,suggesting their potential application as prognostic and predictive biomarkers.The role of microRNAs in lung cancer remains elusive.It has been recently reported that epidermal growth factor receptor （EGFR） and hepatocyte growth factor receptor （MET） tyrosine kinase can regulate expression of specific microRNAs including miR-30b,miR-30c,miR-221,miR-222,miR-103 and miR-203,and induce tumorigenesis and gefitinib resistance in lung cancers.We intend to study the role of miR-30b and miR-30c expression in predicting response to tyrosine kinase inhibitors （TKIs） in non-small cell lung cancer （NSCLC）.Methods We have therefore retrospectively examined expression of miR-30b miR-30c in 41 formalin fixed paraffin embedded tissue samples from NSCLC patients when TKIs were used as first line therapy.Results We found a significant correlation between expression of miR-30b and miR-30c.Furthermore,miR-30b and miR-30c expression correlated with short-term response.Kaplan-Meier analysis further revealed that the expression of miR-30b and miR-30c predicted progression free survival and the overall survival rate in the examined cohort.Conclusion Our study identified miR-30b and miR-30c as useful prognostic predictors in NSCLC patients who underwent first line treatment with TKIs.     

Genetic characterization of a Chinese family with familial idiopathic pulmonary fibrosis

Background  Idiopathic pulmonary fibrosis (IPF) is a chronic inflammatory interstitial lung disease with an unknown cause. Recent studies have shown that genetic factors play an important role in the pathogenesis of IPF.

Methods  To explore the genetic background of patients with IPF, a candidate gene approach was employed to screen for mutations in seven genes among members with familial IPF in mainland of China.

Results  Within six of the candidate genes, a total of 31 point mutations were identified. Among the missense mutations, the SFTPA1 exon 6 CAG>AAG (Gln238Lys) and SFTPB exon 2 CAC>CCC (His2Pro) mutations caused changes in the physical and chemical properties of amino acids. Each sequence alteration was identified in sporadic IPF patients, control specimens (pneumonia patients and healthy persons). Genotype frequencies and allele frequencies of codon 238 in exon 6 of SFTPA1 were noted significantly higher in patients with IPF than those in other two control subjects. The computational protein structure prediction by protein homology modeling confirmed differences in three-dimensional structure between mutant SFTPA1 and original SFTPA1.     

Conclusions  Although the functions of the mutant candidate genes vary, these genes may ultimately result in damage to alveolar epithelial cells, initiating the progress of pulmonary fibrosis. In particular, while pathophysiological mechanisms need to be illustrated, the Gln238Lys missense variant of exon 6 in the SFTPA1 may have potential susceptibility in the development of IPF, which was shown in patients with sporadic IPF with a statistically higher frequency.

     

Tumorigenesis and spontaneous metastasis by luciferase-labeled human xenograft osteosarcoma cells in nude mice

Background  Osteosarcoma (OS) is the most common primary malignant tumor of bone. Mouse models of human OS can invariably provide greater insight into the complex mechanisms that underlie the development and pathogenesis of this aggressive tumor. Bioluminescence technology favored tracing cancer cells in vivo. In this study, an OS model was described and evaluated using human OS cell line, Saos2, labeled with luciferase (Saos2-luc).

Methods  Saos2 cells were infected by lentivirus loading a firefly luciferase gene. Luciferase expression of Saos2-luc cells was characterized both in vitro and in vivo. Specific biologic and oncologic features of Saos2-luc cells were analyzed. The OS was established as orthotopic xenografts in nude mice. Both orthotopic tumors and spontaneous lung metastasis were analyzed.

Results  Tumorigenesis and spontaneous lung metastasis in nude mice could be monitored in vivo through in vivo imaging system. The enhancement in proliferation, migration and invasion abilities and the attenuation in adhesion ability were observed in Saos2-luc cells compared with Saos2 cells. Furthermore, there were the up-regulation of Osteocalcin, CCR10, CXCR1 and ID1 and the down-regulation of ALP, collagen I, CCR1, CCR3, CXCR3, NID and N-cadherin in Saos2-luc cells compare to Saos2 cells. The rate of spontaneous lung metastasis in Saos2-luc cells was higher than that in Saos2 cells, although without significant difference.

Conclusions  Lentivirus transfection may cause alteration of gene expression profiles and further biological functions. This model can be used in the elucidation of molecular mechanisms of tumorigenesis and the screening of new therapeutic agents.

     

Exome sequencing identifies compound heterozygous PKHD1 mutations as a cause of autosomal recessive polycystic kidney disease

Background  Autosomal recessive polycystic kidney disease (ARPKD) is a rare inherited disease, which is a disorder with multiple organ involvement, mainly the kidney and liver. It is caused by mutations in the PKHD1 gene. Here, we reported the clinical characteristics of a case with ARPKD and analyze the genetic features of this patient as well as of his father using targeted exome sequencing and Sanger sequencing.

Methods  Genomic DNA was extracted from peripheral blood leukocytes obtained from a patient with ARPKD. The mutations were identified using exome sequencing and confirmed by Sanger sequencing.

Results  The patient was diagnosed as ARPKD based on ultrasonography and abdominal computed tomography which showed polycystic changes, multiple calcinosis of both kidneys, and multiple dilated bile ducts of the liver. Compound heterozygous PKHD1 gene mutations A979G and G5935A, which lead to substitution of an asparagine for an aspartate at amino acid 327 (N327D) and a glycine for an arginine at amino acid 1979 (G1979R) respectively, were identified using targeted exome sequencing and confirmed by Sanger sequencing for the patient. In addition, the father of the patient was identified to be a carrier of heterozygous A979G mutation of this gene.

Conclusions  We identified that the compound heterozygous PKHD1 gene mutations are the molecular basis of the patient with ARPKD. Targeted exome sequencing is suitable for genetic diagnosis of single-gene inherited diseases like ARPKD in which the pathogenic gene is a large.     

Compound mutations (R237X and L375P) in the fumarylacetoacetate hydrolase gene causing tyrosinemia type I in a Chinese patient

Background  Mutations in fumarylacetoacetate hydrolase (FAH) gene can lead to tyrosinemia type 1 (HT1), a relatively rare autosomal recessive disorder. To date, no molecular genetic defects of HT1 in China have been described. We investigated a Chinese family with a HT1 child to identify mutations in FAH.

Methods  DNA sequencing was used for mutations screening in FAH gene. Real-time polymerase chain reaction (PCR) was performed to determine the FAH gene expression level. To confirm the presence of degradation by the nonsense-mediated mRNA decay pathway (NMD), the fragments containing R237X mutations were analyzed by primer introduced restriction analysis-polymerase chain reaction (PIRA-PCR) and cDNA sequencing. Finally, the effects of the mutations reported in this study were predicted by online softwares.

Results  A boy aged 3 years and 8 months was diagnosed clinically with HT1 based on his manifestations and biochemical abnormalities. Screening of FAH gene revealed two heterozygous mutations R237X and L375P transmitted from his mother and father respectively. In this pedigree, the amount of FAH mRNA relative to a healthy control was 0.44 for the patient, 0.77 for his mother and 1.07 for his father. Moreover, both PIRA-PCR and cDNA sequencing showed significant reduction of the FAH mRNA with R237X nonsense mutation. The missense mutation of L375P was not reported previously and prediction software showed that this mutation decreased the stability of protein structure and affected protein function.

Conclusions  This is the first case of HT1 analyzed by molecular genetics in China. The R237X mutation in FAH down- regulates the FAH gene expression, and the L375P mutation perhaps interrupts the secondary structure of FAH protein.

     

An Asian population-based survival analysis of patients with distal esophageal and gastric cardia adenocarcinomas

Background  Gastroesophageal junction adenocarcinomas include adenocarcinomas of the distal esophagus (DE) and gastric cardia (GC). It is controversial whether these tumors are the same entity and whether they have the same survival rates. Patients with DE and GC adenocarcinomas have a similar survival rate in the US; however, data are lacking in Asian countries. Therefore, we conducted a retrospective study to understand the implications of the tumor location in the survival of Asian patients.

Methods  A total of 209 patients with pathologically confirmed DE and GC adenocarcinomas, from 2005 to 2007, were included in the study. We identified patients with adenocarcinomas of the DE (DE group, n=91) and GC (GC group) (n=118). We performed an unadjusted survival analysis using the Kaplan-Meier method, and used a Cox proportional hazards regression model to adjust for potential confounding covariates.

Results  We found no significant difference between the overall survival of the DE and GC groups. The 3-year survival rates were 44.8% and 53.0%, respectively, and the 5-year survival rates were 27.9% and 30.2%, respectively (P=0.162). We found no significant difference in early staging, advanced staging, different T staging, and different N staging, between the groups. Both advanced post-operative N staging and advanced AJCC staging had a significant adverse effect on survival.

Conclusions  Patients with DE and GC adenocarcinomas have similar survival rates in the Asian population. Both post-operative N staging and AJCC staging are prognostic factors.

     

Transduction of mesenchymal stem cells with multidrug resistance gene provides protection for bone marrow toxicity after being transplanted into a nude mice model

Background  Myelosuppression is the main dose-related toxicity of many chemotherapeutic drugs. The human multidrug resistance (mdr1) gene is well-known for its ability to confering drug resistance. In this study, we meant to transplant the placenta mesenchymal stem cells (P-MSCs) moderated by mdr1 gene into a nude mice model radiated by g-Co⁶⁰ and to explore the chemoprotection for bone marrow (BM) toxicity.

Methods  Human P-MSCs were isolated from trypsin-digested term placentas and then transduced by with reconstructed retroviral vector containing mdr1 gene and green fluorescent protein (GFP) reporter gene. The integration and expression of mdr1 gene was observed indirectedly by the expression of GFP. A nude mice model was constructed after irradiation with a sublethal dosage of g-Co⁶⁰. These irradiated mice were transplanted with mdr1-MSCs through the caudal vein and then received paclitaxel (PAC) intraperitoneal chemotherapy. The Peripheral peripheral blood (PB) of the nude mice was collected, and the PB cells counts and values were determined using an automatic analyzer.

Results  After PAC treatment, mdr1-MSCs transplanted mice showed markedly improved survival upon compared to MSCs transplanted mice (85.7% vs. 57.1%). White blood cell (WBC) and red blood cell (RBC) counts as well as the hemoglobin (Hb) values were significantly increased in PAC treated mdr1-MSCs mice compared to PAC treated control mice when PAC chemotherapy had been finished (all P <0.05), but the difference was not found in the plateltes (PLT) count (P >0.05).

Conclusion  Human P-MSCs moderated by mdr1 gene when transplanted into nude mice may provide chemoprotection for hematopoietic toxicity.

     

Reversal of multidrug resistance in renal cell carcinoma by short hairpin RNA targeting MDR1 gene

Background  Over-expression of P-glycoprotein (P-gp), encoded by the MDR1 gene, confers multidrug resistance (MDR) in renal cell carcinoma (RCC) and is a major reason for unsuccessful chemotherapy. This study aimed to determine the effct of RNA interference (RNAi) on the reversal of MDR in human RCC.

Methods  We designed and selected one short hairpin RNA (shRNA) targeting MDR1 gene, which is stably expressed from integrated plasmid and transfected by lentivirus fluid in human RCC A498 cell.

Results  The MDR1-targeted RNAi resulted in decreased MDR1 gene mRNA level (P <0.001), almost abolished P-gp expression and reversed MDR to different chemotherapy drugs in the RCC A498 cell line.

Conclusion  MDR could be reversed by RNAi in human RCC A498 cell line, which may be used for clinical application in future.

     

Enhanced expression of proneurotrophins in elevated introcular pressure-induced rat retinal ischemia

Background  Proneurotrophins such as the precursor of nerve growth factor (proNGF) and the precursor of brain-derived neurotrophic factor (proBDNF) interacted with sortilin and p75^NTR to form a complex capable of activating an apoptotic signaling. We found that the expression of p75^NTR and sortilin was increased in ischemic retina induced by elevated intraocular pressure (IOP), but the protein expression changes of proNGF and proBDNF in the same situation were not clear. This study aimed to ascertain the protein expression changes of proNGF and proBDNF in ischemic retina induced by elevated IOP.

Methods  Expression of proBDNF and proNGF was examined by double-labeling immunochemistry in normal rat retina, examined using Western blotting and analyzed using statistical methods in ischemic retina induced by elevated IOP.

Results  Immunocytochemistry showed that the proBDNF expressed in the ganglion cell layer (GCL) while the proNGF primarily existsed in both the nerve fiber layers (NFL) and large ganglion cell bodies of normal rat retina. Western blotting analysis demonstrated that the molecule weights of 28 kD (proBDNF) / 25 kD (proNGF) band were increased significantly (P <0.05) at days 3, 5 and 7 after retinal elevated-IOP-induced ischemia.

Conclusion  ProBDNF expressed in the GCL and proNGF primarily presented in NFL and large ganglion cell bodies of normal rat retina, the protein expression forms of 28 kD proBDNF and 25 kD proNGF increased in ischemic retina induced by elevated IOP.

     

Over-expression of small ubiquitin-like modifier proteases 1 predicts chemo-sensitivity and poor survival in non-small cell lung cancer

Background Non-small cell lung cancer （NSCLC） is one of the most common malignant tumors.Despite the advances in therapy over the years,its mortality remains high.The aim of this study was to evaluate the expression of small ubiquitin-like modifier （SUMO） proteases 1 （SENP1） in NSCLC tissues and its role in the regulation of vascular endothelial growth factor （VEGF） expression.We also investigated the association between the expression level of SENP1 and the clinicopathological features and survival of the patients.Methods A SENP1 small interfering RNA （siRNA） was constructed and transfected into the NSCLC cells.VEGF gene expression was analyzed by real-time polymerase chain reaction （RT-PCR）.Immunohistochemistry staining was used to assess the expression of SENP1 in 100 NSCLC patients and its association with the clinicopathological features and survival was analyzed.Results VEGF expression was significantly higher in NSCLC tissues than in normal lung tissues.Inhibition of SENP1 by siRNA was associated with decreased VEGF expression.SENP1 was over-expressed in 55 of the 100 NSCLC samples （55％） and was associated with a moderate and low histological tumor grade （3.6％,38.2％,and 58.2％ in high,moderate and low differentiated tumors,respectively,P=0.046）,higher T stage （10.9％ in T1,and 89.1％ in T2 and T3 tumor samples,P ＜0.001）and TNM stage （10.9％ in stage Ⅰ,and 89.1％ in stages Ⅱ and Ⅲ tumor samples,P ＜0.001）.The rate of lymph node metastasis was significantly higher in the SENP1 over-expression group （76.4％） than that in the SENP1 low expression group （33.3％,P ＜0.001）.Sixty three patients received postoperative chemotherapy,including 34 with SENP1 over-expression and 29 with SENP1 low expression.Among the 34 patients with SENP1 over-expression,22 （64.7％） patients developed recurrence or metastasis,significantly higher than those in the low expression group 27.6％ （8/29） （P=0.005）.Multivariate Cox regression analysis showed     

A single tube modified allele-specific-PCR for rapid detection of erythromycin-resistant Mycoplasma pneumoniae in Beijing

Background  Mycoplasma pneumoniae (M. pneumoniae) is one of the common pathogens causing atypical pneumonia. In recent years, resistance to macrolides has become more common, especially in China. Previous studies have confirmed that the mutation at position 2063 in domain V of the 23S rRNA is the most prevalent, followed by the mutation at position 2064. Reported molecular detection methods for the identification of these mutations include direct sequencing, restriction fragment length polymorphism analysis, real-time polymerase chain reaction (PCR) with high-resolution melt analysis, and nested PCR-linked with capillary electrophoresis, etc. The most commonly used method for monitoring resistance-conferring mutations in M. pneumoniae is direct DNA sequencing of PCR or nested PCR products. However, these methods are time-consuming, labor-intensive or need expensive equipments. Therefore the development of rapid and sensitive methods is very important for monitoring the resistance globally.

Methods  In this study, we reported a fast and cost-effective method for detecting 2063 and/or 2064 macrolide resistant mutations from specimens using a modified allele-specific PCR analysis, and all results were compared with the sequencing data. We also analyzed the clinical courses of these samples to confirm the modified allele-specific PCR results.

Results  Among 97 M. pneumoniae specimens, 88 were found to possess mutations by this method, and all modified allele-specific PCR analysis results were consistent with the sequencing data. The data of the clinical courses of these 97 cases showed that they suffered from severe pneumonia. Erythromycin showed better efficacy on cases from which no macrolide resistance mutation was found on their specimens. However, in some cases from which mutations were detected, erythromycin monotherapy had poor efficacy, and on these patients severe symptoms improved only when azithromycin was added to the treatment.

Conclusions  The drug-resistant M. pneumoniae is very common in Beijing, China. Our modified allele-specific PCR analysis can identify erythromycin resistant mutations more rapidly from specimens than any other method currently available. Erythromycin is still effective for treating patients infected with the mutation negative M. pneumoniae, but this treatment fails to work on mutant organisms. This method can facilitate clinicians in selecting appropriate therapy within short timescales.

     

Antimicrobial resistance and molecular epidemiological characteristics of clinical isolates of Staphylococcus aureus in Changsha area

Background  Increasing prevalence of Staphylococcus aureus (S. aureus), particularly methicillin-resistant S. aureus (MRSA) has been reported in China. In this study, we investigated the drug resistance characteristic, genetic background, and molecular epidemiological characteristic of S. aureus in Changsha.

Methods  Between January 2006 and December 2008, 293 clinical isolates of S. aureus were collected from 11 hospitals in Changsha and identified by the Vitek-2 system. All the isolates were verified as MRSA by PCR amplification of both femA and mecA genes. K-B disk method was used to test drug sensitivity of S. aureus to antibiotics. Pulsed-field gel electrophoresis (PFGE) was performed for genotypic and homologous analysis of 115 isolates randomly selected from the original 293 clinical S. aureus isolates.

Results  S. aureus was highly resistant to penicillin, ampicillin, erythromycin, and clindamycin with resistant rates of 96.6%, 96.6%, 77.1%, and 67.2% respectively. All the isolates were susceptible to tecoplanin, vancomycin, and linezolid. MRSA accounted for 64.8% (190/293) of all the S. aureus strains. The 115 S. aureus isolates were clustered into 39 PFGE types by PFGE typing, with 13 predominant patterns (designated types A to M) accounting for 89 isolates. The most prevalent PFGE type was type A (n=56, 48.7%) and 100.0% of type A strains were MRSA. PFGE type A included 13 subtypes, and the most prevalent subtype was subtype A1 (46.4%, 26/56). Strains with PFGE type A were isolated from eight hospitals (8/11), and both subtypes A1 and A4 strains were isolated in a university hospital.

Conclusions  Clinical isolates of S. aureus in Changsha were resistant to multiple traditional antibiotics. There was an outbreak of PFGE type A MRSA in this area and the A1 subtype was the predominant epidemic clone. Dissemination of the same clone was an important reason for the wide spread of MRSA.     

Relationship of plasminogen activator inhibitor 1 gene 4G/5G polymorphisms to hypertension in Korean women

Background  Hypertension (HTN) is a major determinant of various cardiovascular events. Plasma levels of plasminogen activator inhibitor 1 (PAI-1) modulate this risk. A deletion/insertion polymorphism within the PAI-1 loci (4G/4G, 4G/5G, 5G/5G) affects the expression of this gene. The present study investigated the association between PAI-1 loci polymorphisms and HTN in Korean women.

Methods  Korean women (n=1312) were enrolled in this study to evaluate the association between PAI-1 4G/5G gene polymorphisms and HTN as well as other metabolic risk factors. PAI-1 loci polymorphisms were investigated using polymerase chain reaction amplification and single-strand conformation polymorphism analysis.

Results  The three genotype groups differed with respect to systolic blood pressure (P=0.043), and diastolic blood pressure (P=0.009) but not with respect to age, body mass index, total cholesterol, low or high density lipoprotein cholesterol, triglycerides, or fasting blood glucose. Carriers of the PAI-1 4G allele had more hypertension significantly (PAI-1 4G/5G vs. PAI-1 5G/5G, P=0.032; PAI-1 4G/4G vs. PAI-1 5G/5G, P=0.034). When stratified according to PAI-1 4G/5G polymorphism, there was no significant difference in all metabolic parameters among PAI-1 genotype groups in patients with HTN as well as subjects with normal blood pressure. The estimated odds ratio of the 4G/4G genotype and 4G/5G for HTN was 1.7 (P=0.005), and 1.6 (P=0.015), respectively.

Conclusion  These findings might indicate that PAI-1 loci polymorphisms independently contribute to HTN and that gene-environmental interaction may be not associated in Korean women.

     

Overexpression of glucosylceramide synthase and its significance in the clinical outcome of non-small cell lung cancer

Background Glucosylceramide synthase （GCS）,an enzyme responsible for ceramide glycosylation,plays an important role in multidrug resistance （MDR） in some tumors in vitro; however,its expression and clinicopathological significance in non-small cell lung cancer （NSCLC） remains unclear.Methods We evaluated GCS expression in 116 paired tumor and adjacent non-cancerous tissues and 50 frozen tissues from patients with NSCLC using immunohistochemistry and western blotting,and explored the correlation between GCS and NSCLC clinicopathological characteristics and prognosis.We observed the association between GCS and the MDR proteins P-glycoprotein （P-gp） and lung resistance-related protein （LRP） to determine the link between GCS and MDR at the histological level.Results GCS expression was significantly upregulated in NSCLC tumors compared with non-cancerous tissue.There was high GCS expression in 75/116 tumor specimens （64.7％） and 16/116 non-cancerous specimens （13.8％）.High GCS expression was significantly associated with poor differentiation （P=0.01）,lymph node metastasis （P=0.004）,recurrence/ distant metastasis （P=0.006）,and chemotherapy resistance （P=0.025）.Multivariate analysis demonstrated that GCS immunopositivity was an independent risk factor for survival （P=0.018）.P-gp was expressed in 80/116 tumors （69.0％） and in 12/116 non-cancerous tissue specimens （10.3％; P=0.001）; LRP was expressed in 85/116 tumors （73.3％） and 19/116 non-cancerous tissue specimens （16.4％; P=0.001）.Importantly,the results demonstrated that increased GCS expression in NSCLC cancer specimens correlated with increased expression of P-gp and LRP,molecules known to stimulate cancer cell MDR （r=0.612 and 0.503,P=0.01 and 0.035,respectively）.Conclusion GCS upregulation might contribute to the development of NSCLC and could be a useful prognostic indicator and chemoresistance predictor for NSCLC patients.     

Role of microRNA-181a in the apoptosis of tubular epithelial cell induced by cisplatin 

Background  Cisplatin (DDP) is one of most effective and most commonly used therapeutic agent in treating tumors, it can accumulate in the kidney and lead to acute renal failure. MicroRNA-181a can induce cell apoptosis by suppressing the expression of Bcl-2 family. In the present study, we investigated the role of microRNA-181a in the apoptosis of tubular epithelial cell induced by DDP.

Methods  HK-2 cells were cultured, transfected with microRNA-181a inhibitor for 48 hours, and stimulated with 50 µmol/L cisplatin for 24 hours. MicroRNA-181a expression was analyzed by real time PCR, and cell apoptosis was detected by flow cytometry. Moreover, Bcl-2 and Bcl-2-associated X protein (Bax) expression were measured by Western blotting.

Results  MicroRNA-181a expression significantly down-regulated in cells transfected with microRNA-181a inhibitor, compared with that in untransfectd cells (21.19±2.01 vs. 38.87±1.97, P <0.05). Cell apoptosis induced by DDP significantly decreased in cells transfected with MicroRNA-181a inhibitor. Compared with DDP treated cells alone, Bcl-2 expression strikingly was up-regulated and Bax expression was down-regulated in cells transfected with microRNA-181a inhibitor.

Conclusion  One pathway of DDP induces apoptosis of tubular epithelial cell by suppressing Bcl-2 expression is achieved by regulating the target gene of MicroRNA-181a.

     

法呢基转移酶在原发性肝癌中的表达

Background  Primary liver cancer (PLC) is a common malignant tumor. Over the past decade, although farnesyltransferase (FTase) has emerged as a significant target for anticancer therapies and has become a hotspot of cancer research, its exact mechanism of action remains unknown. The aim of this study was to investigate the expression of FTase in PLC and its role in the development of PLC.

Methods  Expression of FTase was detected by real-time fluorescent quantitative-polymerase chain reaction (FQ-PCR) in cancer and surrounding normal tissues from 32 patients with PLC.

Results  Expression of FTase mRNA in PLC was significantly higher than that in normal hepatic tissues (P <0.001). Overexpression of FTase was as high as 87.5%. The positive rate for FTase mRNA in the high tendency to metastatic recurrence group was obviously higher than that in the low tendency to metastatic recurrence group (P=0.02). The positive rate for FTase mRNA in patients with metastatic recurrence during postoperative follow-up was also significantly higher than that in those without metastatic recurrence (P=0.01).

Conclusions  The level of FTase mRNA expression in cancer tissues is much higher than in normal tissues. FTase may play an important role in the genesis and development of PLC and may be one of the reliable markers for the metastatic activity gained by liver tumor cells. FTase could be used clinically in predicting metastatic recurrence of PLC.