Aberrant DNA methyltransferase 1 expression in clear cell renal cell carcinoma development and progression

Objective： To better understand the contribution of dysregulated DNA methyltransferase 1 （DNMT1） expression to the progression and biology of clear cell renal cell carcinoma （ccRCC）. Methods： We examined the differences in the expression of DNMT1 in 89 ecRCC and 22 normal tissue samples by immunohistochemistry. In addition, changes in cell viability, apoptosis, colony formation and invading ability of ccRCC cell lines （786-0 and Caki-1） were assessed after transfection with DNMT1 siRNA. Results： We found DNMT1 protein was significantly higher expressed in ccRCC than that of in no-tumor tissues （56.2% and 27.3%, respectively, P=0.018）. The expression of DNMT1 was strongly associated with ccRCC tumor size, tumor pathology stage, histological grading, lymph node metastasis, vascular invasion, recurrence and prognosis. Moreover, knockdown of DNMT1 expression significantly inhibited ccRCC cell viability, induced apoptosis, decreased colony formation and invading ability. Conclusions： Expression of DNMTI protein is increased in ccRCC tissues, and DNMT1 expression is associated with poor prognosis of patients. Experiments in vitro further showed DNMT1 played an essential role in proliferation and invasion of renal cancer cells. Moreover, targeting this enzyme could be a promising strategy for treating ccRCC, as evidenced by inhibited cell viability, increased apoptosis, decreased colony formation and invading ability.     

Genomic profiling in pancreatic ductal adenocarcinoma and a pathway towards therapy individualization: A scoping review

ContextPancreatic cancer (PDAC) is one of the most challenging cancers to treat with modest recent improvements in survival from new systemic therapies. There is growing interest in individualized therapy underpinned by somatic and germline genomic alterations.ObjectiveA systematic review of data on therapies targeting somatic and germline alterations, and their downstream pathways in PDAC.MethodA systematic literature search was conducted using PRISMA guidelines to include relevant results published after January 1, 2008.ResultsA total of 71 relevant studies were included. We identified 36 studies targeting the KRAS-pathway, the most common being with MEK-inhibitor therapy. Twenty-two studies were identified that evaluated platinum-based chemotherapy and PARP inhibitors in patients with deleterious mutations in DNA damage repair genes and have shown encouraging results. Immunotherapy has demonstrated activity in patients with mismatch repair deficiency/microsatellite instability.ConclusionEvidence from translational and clinical research presents an exciting platform for genomic targeted therapy in PDAC. Validity for targeting BRCA with platinum and PARP inhibitors and microsatellite instability with immune therapy has been established, nonetheless, evidence for targeting the common driver oncogenes is lacking and much work is needed. Of importance is identifying the subgroup of KRAS -wild type PDAC (approximately 5%) where there is enrichment for targetable opportunities.     

Outcomes of robotic surgery for pancreatic ductal adenocarcinoma

Background

To explore the effectiveness, safety, and efficacy of the robot-assisted surgery in the radical resection of pancreatic ductal adenocarcinoma (PDAC).

Methods

The clinical data of 72 patients with PDAC who underwent radical resection using the da Vinci Surgical System from April 2010 to December 2014 were retrospectively analyzed.

Results

Among these 72 patients, three were converted to conventional laparotomy due to the vascular invasion or due to the difficulties in tissue isolation from the surrounding organs. Among 39 patients who underwent the pancreatoduodenectomy, the average operative time was 395.3±118.8 min, and the mean intra-operative blood loss was 447.3±269.9 mL. Among 31 patients who underwent the distal pancreatectomy (DP), the average operative time was 185.5±74.1 min, and the mean intra-operative blood loss was 267.1±305.3 mL. In two patients who received the middle pancreatectomy (MP), the average operative time was 225 min and mean intra-operative blood loss was 100 mL. Among all the 72 patients, an average of 4.2±2.6 lymph nodes were dissected, with an average hospital stay of 22.6±10.7 days. Complications were observed in 18 patients, which included pancreatic fistula (n=11), bile leak (n=5), anastomotic bleeding (n=2), pancreatic fistula complicated with portal vein thrombosis (n=1), and anastomotic bleeding complicated with acute renal failure (n=1). Except that one patient died due to post-operative bleeding and acute renal failure, all the other patients were cured after conservative treatment. These 72 patients were followed for 1-45 (15.6±5.8) months, during which 10 patients died. Eleven patients suffered from recurrence or metastasis, among which 6 had local recurrence, 4 had liver metastasis, and 1 had ascites accompnaied with incision site tumor metastasis.

Conclusions

Radical resection of PDAC by robotic surgical system is safe and feasible. It has less surgical trauma and enables faster post-operative recovery, and therefore can achieve the lymph node dissection scope and tumor resection margin required by the standards of radical resection for pancreatic cancer. Nevertheless, its long-term efficacy requires further validation.     

ACTR3 promotes cell migration and invasion by inducing epithelial mesenchymal transition in pancreatic ductal adenocarcinoma

BackgroundRecurrence and metastasis are the major causes of pancreatic ductal adenocarcinoma (PDAC) mortality after treatment. The underlying molecular mechanism is poorly understood. Actin-related protein 3 (ACTR3) is an important component of the actin-related protein 2/3 complex, which is involved in the regulation of cell motility and epithelial mesenchymal transition (EMT) process. Previously published studies have indicated that ACTR3 expression is upregulated in several types of cancers, and promotes tumor development, including gastric cancer and hepatocellular carcinoma. However, to date, the expression levels and the role of ACTR3 in PDAC are not well understood.MethodsIn the present study, the expression levels of ACTR3 in PDAC tissue and the relationship of ACTR3 expression with clinical prognosis were analyzed by mRNA microarray and bioinformatics. The biological functions and underlying mechanism of ACTR3 in PDAC were examined by a series of assays, including Cell Counting Kit-8 (CCK-8), transwell assay, and Western blotting.ResultsWe found that the expression of ACTR3 was significantly increased in PDAC tissues and cell lines. A higher expression of ACTR3 was predictive of poor outcome for patients with PDAC. In vitro, the knockdown of ACTR3 expression significantly inhibited the invasive and migratory capacity of PDAC cells, and altered the distribution of F-actin and the expression of EMT markers.ConclusionsThe findings of our study indicated that ACTR3 promotes cell migration and invasion by inducing EMT in PDAC, which may be a potential therapeutic target and prognostic indicator for PDAC patients.     

Association of increased DNA methyltransferase expression with carcinogenesis and poor prognosis in pancreatic ductal adenocarcinoma

Introduction  

Epigenetic modifications play an important role in multistage carcinogenesis. The role of the three functional DNA methyltransferases (DNMTs) in pancreatic carcinogenesis has not been fully understood. The main goal of this study was to examine DNMT expression in different stages of pancreatic ductal adenocarcinoma (PDAC), and evaluate their prognostic significance in PDAC.     

ECT2基因在人胰腺导管腺癌中的表达及对胰腺癌细胞生物学特性的影响

[摘要] 目的：探讨上皮细胞转化序列2（epithelial cell transforming 2,ECT2）基因在人胰腺导管腺癌（pancreatic ductal adenocarcinoma,PDAC）中的表达及其对胰腺癌细胞增殖、凋亡的影响。方法：采集2018 年7 月至2019 年3 月在海军军医大学附属长海医院病理科PDAC及相应癌旁样本各35 例。通过GEO数据库中人胰腺癌基因表达谱筛选差异表达基因,采用TCGA数据分析该基因在PDAC中的表达及与患者生存的相关性。以qPCR及免疫组化在人PDAC样本中验证了ECT2 mRNA及蛋白的表达。以siRNA干扰人胰腺癌细胞系PANC-1 中ECT2 基因的表达,CCK-8 增殖实验检测肿瘤细胞增殖,流式细胞术检测对胰腺癌细胞凋亡的影响,最后WB检测凋亡相关蛋白的变化。结果：生物信息学分析筛选出胰腺癌中差异表达基因ECT2,TCGA数据库分析发现其在癌组织中高表达（t=4.005,P<0.05）并与生存显著相关（P<0.01）。mRNA（1.01±0.06 vs 4.25±0.12,t=24.09,P<0.01）及蛋白水平验证其在人PDAC样本中高表达。干扰ECT2 基因后,其细胞增殖受到明显抑制（P<0.01）、他莫昔芬诱导的细胞凋亡显著增加（P<0.01）,同时影响凋亡相关蛋白BAX及BCL-2 的表达。结论：ECT2 基因在人PDAC中高表达并与患者生存相关,其增加了胰腺癌细胞的增殖及抗凋亡能力。本结果为探讨ECT2 作为胰腺癌预后判断及治疗新靶点提供了实验依据。     

A phase II trial of GSK2256098 and trametinib in patients with advanced pancreatic ductal adenocarcinoma

BackgroundMitogen-activated protein kinase kinase (MEK) is activated by mutated KRAS in >90% of pancreatic ductal adenocarcinoma (PDAC). MEK and focal adhesion kinase (FAK) are frequently co-activated in PDAC providing a rationale for combining trametinib, an oral allosteric MEK1/2 inhibitor, with GSK2256098, an oral FAK inhibitor.MethodsAdvanced PDAC patients whose disease progressed after first line palliative chemotherapy were treated with GSK2256098 250 mg twice daily and trametinib 0.5 mg once daily orally. The primary endpoint was clinical benefit (CB; complete response, partial response, or stable disease ≥24 weeks). Twenty-four patients were planned to enroll using a 2-stage minimax design (P₀=0.15, P₁=0.40; alpha =0.05, power 0.86). The combination would be considered inactive if 2/12 or fewer patients achieved CB at the end of stage 1, and would be considered active if >7/24 response-evaluable patients achieved CB by the end of stage 2. Serial blood samples were collected for circulating tumor DNA (ctDNA) mutation profiling.ResultsSixteen patients were enrolled and 11 were response evaluable. Of those 11, 10 had progressive disease as best tumor response and one had stable disease for 4 months. No treatment related grade ≥3 adverse events (AEs) were observed. The median progression free survival (PFS) was 1.6 (95% CI: 1.5–1.8) months and the median overall survival (OS) was 3.6 (95% CI: 2.7–not reached) months. One response-inevaluable patient achieved clinical stability for 5 months with reduction in CA19-9 and ctDNA levels with a MAP2K1 treatment resistance mutation detected in ctDNA at clinical progression.ConclusionsThe combination of GSK2256098 and trametinib was well tolerated but was not active in unselected advanced PDAC.     

hERG1 channels drive tumour malignancy and may serve as prognostic factor in pancreatic ductal adenocarcinoma

Background:

hERG1 channels are aberrantly expressed in human cancers. The expression, functional role and clinical significance of hERG1 channels in pancreatic ductal adenocarcinoma (PDAC) is lacking.

Methods:

hERG1 expression was tested in PDAC primary samples assembled as tissue microarray by immunohistochemistry using an anti-hERG1 monoclonal antibody (α-hERG1-MoAb). The functional role of hERG1 was studied in PDAC cell lines and primary cultures. ERG1 expression during PDAC progression was studied in Pdx-1-Cre,LSL-Kras^G12D/+,LSL-Trp53^R175H/+ transgenic (KPC) mice. ERG1 expression in vivo was determined by optical imaging using Alexa-680-labelled α-hERG1-MoAb.

Results:

(i) hERG1 was expressed at high levels in 59% of primary PDAC; (ii) hERG1 blockade decreased PDAC cell growth and migration; (iii) hERG1 was physically and functionally linked to the Epidermal Growth Factor-Receptor pathway; (iv) in transgenic mice, ERG1 was expressed in PanIN lesions, reaching high expression levels in PDAC; (v) PDAC patients whose primary tumour showed high hERG1 expression had a worse prognosis; (vi) the α-hERG1-MoAb could detect PDAC in vivo.

Conclusions:

hERG1 regulates PDAC malignancy and its expression, once validated in a larger cohort also comprising of late-stage, non-surgically resected cases, may be exploited for diagnostic and prognostic purposes in PDAC either ex vivo or in vivo.     

黏蛋白4在胰腺上皮内瘤变和胰腺癌中的表达差异性分析

目的 探讨黏蛋白4（MUC4）在胰腺上皮内瘤变（PanINs）和胰腺导管腺癌（PDAC）中的表达及临床意义。方法 收集2009年3月1日至2011年12月31日第二军医大学附属长征医院的胰腺组织蜡块标本共85例。采用免疫组化SP法检测MUC4在48例正常胰腺导管（NP）、17例PanINs及20例PDAC组织中的表达情况。分析MUC4的表达与PDAC临床病理特征及预后的关系。结果 MUC4在NP组织中不表达;随着胰腺组织异型程度的增加,MUC4的表达逐渐增强;MUC4在NP、PanIN-1、PanIN-2、PanIN-3及PDAC组织中的阳性表达率分别为0、17.4%、52.6%、84.6%和90.0%;免疫组化评分分别为0、1.30±089、2.58±1.76、4.54±1.64和7.68±2.34,组间比较差异有统计学意义（P＜0.001）。MUC4在PDAC组织中的表达与神经浸润（P=0.028）、淋巴结转移（P=0.020）和CA19-9（P=0.028）有关。20例PDAC患者的中位总生存时间为17.0个月（95%CI：14.809～19.191个月）;MUC4高表达者（免疫组化评分≥8.8分）为13.0个月（95%CI：7.456～18.544个月）,MUC4低表达者（免疫组化评分＜8.8分）为20.0个月（95%CI：15.521～24.479个月）,差异有统计学意义（P=0.003）。结论 MUC4可能参与了PDAC的发生、发展,其表达升高可能是PDAC演进的早期事件,MUC4高表达可能对PDAC的浸润和转移均有影响并提示预后不良。     

Stromal galectin-1 expression is associated with long-term survival in resectable pancreatic ductal adenocarcinoma

The overall 5 year survival rate for pancreatic ductal adenocarcinoma (i.e., PDAC) is a dismal 5%, although patients that have undergone surgical resection have a somewhat better survival rate of up to 20%. Very long-term survivors of PDAC (defined as patients with ≥ 10 year survival following apparently curative resection), on the other hand, are considerably less frequent. The molecular characteristics of very long-term survivors (VLTS) are poorly understood, but might provide novel insights into prognostication for this disease. In this study, a panel of five VLTS and stage-matched short-term survivors (STS, defined as disease-specific mortality within 14 months of resection) were identified, and quantitative proteomics was applied to comparatively profile tumor tissues from both cohorts. Differentially expressed proteins were identified in cancers from VLTS vs. STS patients. Specifically, the expression of galectin-1 was 2-fold lower in VLTS compared with STS tumors. Validation studies were performed by immunohistochemistry (IHC) in two additional cohorts of resected PDAC, including: 1) an independent cohort of VLTS and 2) a panel of sporadic PDAC with a considerable range of overall survival following surgery. Immunolabeling analysis confirmed that significantly lower expression of stromal galectin-1 was associated with VLTS (p = 0.02) and also correlated with longer survival in sporadic, surgically-treated PDAC cases (hazard ratio = 4.9, p = 0.002). The results from this study provide new insights to better understand the role of galectin-1 in PDAC survival, and might be useful for rendering prognostic information, and developing more effective therapeutic strategies aimed at improving survival.     

MicroRNAs in stool samples as potential screening biomarkers for pancreatic ductal adenocarcinoma cancer

Pancreatic ductal adenocarcinoma (PDAC) accounts for approximately 90-95% exocrine malignant tumors of the pancreas. The high prevalence of metastasis and the difficulty of early diagnosis lead to a dismal prognosis. MicroRNAs (miRNAs) play a critical role in extensive biological processes. The purpose of this study was to evaluate the feasibility of stool miRNAs as novel biomarker for PDAC screening. MiRNAs were extracted from clinical specimens which included cancer and matched adjacent benign pancreatic tissues of 30 PDAC patients, pancreatic juice of 20 from the 30 PDAC patients and 10 chronic pancreatitis (CP) patients, stool samples of the 30 PDAC patients, the 10 CP patients and 15 healthy volunteers. Relative expression of a panel of 5 dysregulated miRNAs (miR-21, miR-155, miR-196a, miR-216 and miR-217) was analyzed with qRT-PCR. Receiver operating characteristic curve (ROC) analysis was performed to assess the diagnosing value of stool miRNAs in PDAC patients. The study showed that our methods of extracting and detecting miRNAs from pancreatic juice and stool specimens had high reproducibility. Compared to matched adjacent benign pancreatic tissues and pancreatic juice of CP patients, the expression of miR-21 (P = 0.0021 and P = 0.0027) as well as miR-155 (P = 0.0087 and P = 0.0067) was significantly higher and the expression of miR-216 (P < 0.0001 and P = 0.0044) was significantly lower in primary tumor tissues and pancreatic juice of PDAC patients. PDAC patients had a significantly higher stool miR-21 and miR-155 (P = 0.0049 and P = 0.0112) and lower miR-216 level (P = 0.0002) compared to normal controls. The same results were obtained in the expression levels of stool miR-21, miR-155 and miR-216 between PDAC and CP patients (P = 0.0337, P = 0.0388 and P = 0.0117, respectively). Receiver operating characteristic (ROC) analysis by using stool miRNAs expression indicated that combination of miR-21 and miR-155 had best sensitivity of 93.33% while the combination of miR-21, miR-155 and miR-216 would be best for detecting and screening PDAC with area under the curve (AUC) of 0.8667 (95% CI: 0.7722-0.9612) and a better balance of sensitivity and specificity (83.33% vs. 83.33%). Our data indicate that miRNAs could be extracted and detected from pancreatic juice and stool efficiently and reproducibly. MiR-21, miR-155 and miR-216 in stool have the potential of becoming biomarkers for screening PDAC.     

GOT1/AST1 expression status as a prognostic biomarker in pancreatic ductal adenocarcinoma

Prognostication in pancreatic ductal adenocarcinoma (PDAC) remains a challenge. Recently, a link between mutated KRAS and glutamic-oxaloacetic transaminase (GOT1/AST1) has been described as part of the metabolic reprogramming in PDAC. The clinical relevance of this novel metabolic KRAS-GOT1 link has not been determined in primary human patient samples. Here we studied the GOT1 expression status as a prognostic biomarker in PDAC. We employed three independent PDAC cohorts with clinicopathological- and follow-up data: a) ICGC, comprising 57 patients with whole-exome sequencing and genome-wide expression profiling; b) ULM, composed of 122 surgically-treated patients with tissue-samples and KRAS status; c) a validation cohort of 140 primary diagnostic biopsy samples. GOT1 expression was assessed by RNA level (ICGC) or immunolabeling (ULM/validation cohort). GOT1 expression varied (ICGC) and correlation with the KRAS mutation- and expression status was imperfect (P = 0.2, ICGC; P = 0.8, ULM). Clinicopathological characteristics did not differ when patients were separated based on GOT1 high vs. low (P = 0.08–1.0); however, overall survival was longer in patients with GOT1-expressing tumors (P = 0.093, ICGC; P = 0.049, ULM). Multivariate analysis confirmed GOT1 as an independent prognostic marker (P = 0.009). Assessment in univariate (P = 0.002) and multivariate models in the validation cohort (P = 0.019), containing 66% stage IV patients, confirmed the independency of GOT1.We propose the GOT1 expression status as a simple and reliable prognostic biomarker in pancreatic ductal adenocarcinoma.     

The promise and failures of epigenetic therapies for cancer treatment

Genetic mutations and gross structural defects in the DNA sequence permanently alter genetic loci in ways that significantly disrupt gene function. In sharp contrast, genes modified by aberrant epigenetic modifications remain structurally intact and are subject to partial or complete reversal of modifications that restore the original (i.e. non-diseased) state. Such reversibility makes epigenetic modifications ideal targets for therapeutic intervention. The epigenome of cancer cells is extensively modified by specific hypermethylation of the promoters of tumor suppressor genes relative to the extensive hypomethylation of repetitive sequences, overall loss of acetylation, and loss of repressive marks at microsatellite/repeat regions. In this review, we discuss emerging therapies targeting specific epigenetic modifications or epigenetic modifying enzymes either alone or in combination with other treatment regimens. The limitations posed by cancer treatments elicit unintended epigenetic modifications that result in exacerbation of tumor progression are also discussed. Lastly, a brief discussion of the specificity restrictions posed by epigenetic therapies and ways to address such limitations is presented.     

DNA methyltransferase expression and DNA hypermethylation in human hepatocellular carcinoma

Aberrant DNA methylation and increased expression of DNA methyltransferases (DNMTs) are features of tumor cells. To investigate roles for DNMTs during hepatocarcinogenesis, we examined DNMT expression at both the mRNA and protein level in hepatocellular carcinomas (HCCs) and paired non-neoplastic liver tissues, along with measuring the DNA methylation status of five tumor suppressor genes. Expression of DNMT1, DNMT3a and DNMT3b mRNA was detected in 33.3, 59.3, and 55.6% of HCCs and 40.7, 22.2, and 0% of non-neoplastic liver tissues, respectively. DNMT1 and DNMT3a were immunoreactive in 100 and 48% of HCCs and 52 and 0% of non-neoplastic liver tissues. The DNMT3a mRNA expression profile showed significant correlation with its immunoreactivity (P=0.022). DNA methylation status of five tumor suppressor genes, HIC-1, p16, RASSF1A, p53, and RB1 was detected in 85.2, 48.1, 44.4, 22.2, and 0% of HCCs, respectively. There was no significant correlation between DNMT mRNA expression and DNA methylation (P>0.05). DNMT immunoreactivity was also not associated with DNA methylation except HIC-1 (P=0.036) and p53 methylation (P=0.009). Despite the lack of correlation between DNA methylation status and DNMT expression, the frequency of hypermethylation of tumor suppressor genes remained relatively high in HCCs, suggesting that regional DNA hypermethylation is involved in hepatocarcinogenesis and that there may be other mechanisms for increasing DNA methylation.     

Prognostic value of paraaortic lymph node metastases in patients with ductal adenocarcinoma of the pancreatic head

IntroductionThe role of paraaortic lymphadenectomy for cancer of the pancreatic head is controversial. The aim of this study is to analyze the prognostic role of paraaortic lymph node (PALN) metastases after resection for ductal adenocarcinoma of the pancreatic head.Materials and methodsA retrospective analysis of all patients, who underwent upfront resection for ductal adenocarcinoma of the pancreatic head at the Frankfurt University Hospital from 2011 to 2020 was performed. The primary endpoint was survival, according to the presence of PALN metastases.ResultsOut of 468 patients with pancreatic resection, 148 had an upfront resection for ductal adenocarcinoma. Of those, in 125 (85%) a paraaortic lymphadenectomy was performed. In 19 (15.2%) PALN metastases were detected. The estimated overall median survival after resection was 21.7 months (95% CI 18.8 to 26.4), the disease free survival 16 months (95% CI 12 to 18). Among the patients with lymph node metastases, PALN metastases had no significant influence on overall (18.9 versus 19 months, HR = 1.3, 95% CI 0.7 to 2.6, p = 0.392) or disease free survival (14 versus 10.7 months, HR = 1.7, 95% CI 0.9 to 3.2, p = 0.076). After adjusting for T-stage, N-stage, grade, resection margin, PALN metastases, and adjuvant therapy, only adjuvant therapy had a prognostic significance for overall survival (HR = 0.47, 95% CI 0.26 to 0.85, p = 0.013).ConclusionPatients with ductal adenocarcinoma of the pancreatic head and PALN metastases do not have inferior outcomes than those with regional lymph node metastases. Thus, positive PALN should not be considered a contraindication for resection.     

KRT6A调控胰腺导管腺癌细胞生物学行为的作用及作为诊断与预后判断靶标的研究

目的：通过生物信息学分析以及细胞生物学实验研究角蛋白6A（KRT6A）对胰腺导管腺癌（PDAC）诊断、预后判断、免疫微环境以及PDAC 细胞PANC1 增殖、凋亡等生物学行为的影响。方法：通过GEPIA 平台整合TCGA（The Cancer Genome Atlas）数据库与GTEx（Genotype-Tissue）数据库中的数据,分析KTRT6A在PDAC组织中的表达情况,并通过CIBERSORT工具分析KRT6A表达与PDAC组织中免疫细胞浸润的关系,然后通过GSEA方法研究与KRT6A基因表达相关的肿瘤信号通路。选取长海医院病理科保存的60 例PDAC 组织与癌旁组织标本进行免疫组化分析,验证KRT6A在肿瘤组织中表达情况;通过干扰RNA敲减PANC1细胞中KRT6A的表达,采用CCK-8实验以及流式细胞术检测敲减KRT6A对细胞的增殖、凋亡的影响。结果：利用TCGA与GTEx数据库数据分析发现,KRT6A在人PDAC组织中呈高表达,且与患者较差的生存期存在关联（P=0.015）。利用CIBERSORT 软件以及GSEA 分析发现,KRT6A 高表达的PDAC组织中M2型巨噬细胞浸润性升高（P=0.034）,且与Wnt 通路（NES:1.7359272,P<0.05）、磷酸戊糖途径（PPP）（NES:1.5613053,P<0.05）等信号通路上调有关联（P<0.05 或P<0.01）;免疫组化结果进一步验证了KRT6A在PDAC组织中呈高表达（P<0.001）。增殖和凋亡实验发现,干扰KRT6A能够显著抑制PANC1细胞的增殖（P<0.05）以及凋亡（P<0.001）。结论：KRT6A在人PDAC组织中呈高表达,敲减其表达能够抑制PANC1细胞的增殖和凋亡,具有作为PDAC诊断与预后判断新靶标的潜力。     

OSI-027 inhibits pancreatic ductal adenocarcinoma cell proliferation and enhances the therapeutic effect of gemcitabine both in vitro and in vivo

Despite its relative rarity, pancreatic ductal adenocarcinoma (PDAC) accounts for a large percentage of cancer deaths. In this study, we investigated the in vitro efficacy of OSI-027, a selective inhibitor of mammalian target of rapamycin complex 1 (mTORC1) and mTORC2, to treat PDAC cell lines alone, and in combination with gemcitabine (GEM). Similarly, we tested the efficacy of these two compounds in a xenograft mouse model of PDAC. OSI-027 significantly arrested cell cycle in G0/G1 phase, inhibited the proliferation of Panc-1, BxPC-3, and CFPAC-1 cells, and downregulated mTORC1, mTORC2, phospho-Akt, phospho-p70S6K, phospho-4E-BP1, cyclin D1, and cyclin-dependent kinase 4 (CDK4) in these cells. Moreover, OSI-027 also downregulated multidrug resistance (MDR)-1, which has been implicated in chemotherapy resistance in PDAC cells and enhanced apoptosis induced by GEM in the three PDAC cell lines. When combined, OSI-027 with GEM showed synergistic cytotoxic effects both in vitro and in vivo. This is the first evidence of the efficacy of OSI-027 in PDAC and may provide the groundwork for a new clinical PDAC therapy.