Targeting the facilitative glucose transporter GLUT1 inhibits the self-renewal and tumor-initiating capacity of cancer stem cells

Increased glucose metabolism is now recognized as an emerging hallmark of cancer. Recent studies have shown that glucose metabolism is even more active in cancer stem cells (CSCs), a rare population of cancer cells with the capacity to self-renew and initiate tumors, and that CSCs are dependent on glycolysis for their survival/growth. However, the role of glucose metabolism in the control of their self-renewal and tumor-initiating capacity per se still remains obscure. Moreover, much remains unknown as to which of the numerous molecules involved in the glucose metabolism is suitable as a target to control CSCs. Here we demonstrate that the facilitative glucose transporter GLUT1 is essential for the maintenance of pancreatic, ovarian, and glioblastoma CSCs. Notably, we found that WZB117, a specific GLUT1 inhibitor, could inhibit the self-renewal and tumor-initiating capacity of the CSCs without compromising their proliferative potential in vitro. In vivo, systemic WZB117 administration inhibited tumor initiation after implantation of CSCs without causing significant adverse events in host animals. Our findings indicate GLUT1-dependent glucose metabolism has a pivotal role not only in the growth and survival of CSCs but also in the maintenance of their stemness and suggest GLUT1 as a promising target for CSC-directed cancer therapy.     

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。     

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。     

Understanding the immune landscape and tumor microenvironment of pancreatic cancer to improve immunotherapy

Immunotherapy has revolutionized cancer treatment for several hematologic and solid organ malignancies; however, pancreatic cancer remains unresponsive to conventional immunotherapies. Several characteristics of pancreatic cancer present challenges to successful treatment with immunotherapy, including its aggressive biology, poor immunogenicity, and abundant desmoplastic stroma which can impede effector T cell infiltration and promote an immunosuppressive microenvironment. In this review, we evaluate the current understanding of the immune and stromal landscapes of pancreatic cancer, discuss the successes and failures of stroma-targeted therapies, and highlight how stroma-directed therapies may be synergistic with immunotherapy.     

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.     

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。     

Removal of gemcitabine-induced senescent cancer cells by targeting glutaminase1 improves the therapeutic effect in pancreatic ductal adenocarcinoma

Insufficient cancer treatment can induce senescent cancer cell formation and treatment resistance. The characteristics of induced senescent cancer (iSnCa) cells remain unclear. Pancreatic ductal adenocarcinoma (PDAC) has a low and nondurable response rate to current treatments. Our study aimed to analyze the properties of iSnCa cells and the relationship between cellular senescence and prognosis in PDAC. We evaluated the characteristics of gemcitabine-induced senescent cancer cells and the effect of senescence-associated secretory phenotype (SASP) factors released by iSnCa cells on surrounding PDAC cells. The relationship between cellular senescence and the prognosis was investigated in 50 patients with PDAC treated with gemcitabine-based neoadjuvant chemotherapy. Exposure to 5 ng/mL gemcitabine-induced senescence, decreased proliferation and increased senescence-associated β-galactosidase-cell staining without cell death in PDAC cells; the expression of glutaminase1 (GLS1) and SASP factors also increased and caused epithelial-mesenchymal transition in surrounding PDAC cells. iSnCa cells were selectively removed by the GLS1 inhibitor bis-2-(5-phenylacetamido-1,2,4-thiadiazol-2-yl)ethyl sulfide (BPTES) through apoptosis induction. Cellular senescence was induced in PDAC cells via insufficient gemcitabine in subcutaneous tumor model mice. GLS1 expression was an independent prognostic factor in patients with PDAC who received gemcitabine-based neoadjuvant chemotherapy. This is the first study to identify the relationship between senescence and GLS1 in PDAC. Low-dose gemcitabine-induced senescence and increased GLS1 expression were observed in PDAC cells. Cellular senescence may contribute to treatment resistance of PDAC, hence targeting GLS1 in iSnCa cells may improve the therapeutic effect.     

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.     

Late recurrences of pancreatic cancer in patients with long-term survival after pancreaticoduodenectomy

BackgroundPancreatic cancer remains a relevant clinical problem due to poor prognosis. Even after curative pancreaticoduodenectomy tumor recurrences occur in up to 80%. Risk factors for postoperative tumor recurrences have been identified before, but data on risk factors for tumor recurrences in patients with long-term-survival is scarce.MethodsIn this retrospective study consecutive long-term survival-patients (defined as at least 60 months survival) undergoing pancreaticoduodenectomy for pancreatic cancer from 2007–2014 were identified in the 2nd largest pancreatic surgery center in Germany. Clinical, pathohistological and laboratory values were analyzed to identify risk factors for tumor recurrence.ResultsThirty-four of one-hundred-sixty-seven patients were identified as long-term-survival-patients in the study period. Of those, 10 patients (29.4%) suffered from tumor recurrence. Lymph vessel invasion was identified as an independent risk factor (P=0.031, hazard ratio 13.127, 95% confidence interval: 1.270–135.698). Median postoperative time to tumor recurrence in long-term-survival-patients was 49 months. Overall survival after diagnosis of tumor recurrence was 33 months. 80% (N=8) of the patients were asymptomatic. Half of the patients (N=5) suffered from local disease, with 40% undergoing curative tumor resection. CA 19-9 levels were significantly elevated at 57 U/mL (normal <27 U/mL).ConclusionsTumor recurrence in long-term-survival-patients is typically asymptomatic. Especially long-term-survival-patients with lymph vessel invasion are more likely to develop tumor recurrence. Therefore, a structured follow-up program including CT-scans and CA 19-9 surveillance must be continued in all patients undergoing pancreaticoduodenectomy even in cases of long-term-survival.     

Nerve growth factor and enhancement of proliferation,invasion, and tumorigenicity of pancreatic cancer cells

Nerve growth factor (NGF) exerts both stimulatory and inhibitory effects on neuronal and certain non-neuronal tumors. In pancreatic cancer NGF is overexpressed, and this overexpression is associated with increased perineural invasion. NGF has the potential to stimulate the growth of some pancreatic cancer cell lines, and this effect is mediated by the phosphorylation of tyrosine kinase receptor A and mitogen-activated protein kinase activation; it is dependent on the expression levels of tyrosine kinase receptor A and p75 receptors. To determine whether cancer cell-derived NGF can participate in the regulation of pancreatic cancer cell proliferation, PANC-1 human pancreatic cancer cells were stably transfected with a full-length human beta-NGF expression vector. In vitro and in vivo growth characteristics were analyzed by proliferation assays and invasion assays and in a nude mouse tumor model. Stable transfection of NGF in PANC-1 cells resulted in enhanced anchorage-dependent growth, with a decrease in doubling times of up to 50%, and in an approximately twofold increase in anchorage-independent cell growth and cell invasion. Furthermore, stably transfected PANC-1 cells showed enhanced tumorigenicity in nude mice. These results suggest that NGF has the capacity to act in a paracrine and/or an autocrine manner in pancreatic cancer and that it enhances cancer cell growth and invasion in vivo, thereby contributing to the aggressiveness and poor prognosis of this disease.     

PanGen-Fam: Spanish registry of hereditary pancreatic cancer

PurposeTo describe the organisation of the registry and the preliminary results in terms of characteristics of high-risk pancreatic ductal adenocarcinoma (PDAC) families recruited to date and findings of the screening programme. To compare early onset sporadic cases (⩽50 years), sporadic cases (>50 years) and cases with family history of cancer, for PDAC possible risk factors.Methods/patientsFamilies with hereditary cancer syndromes predisposing to PDAC were recruited from two main sources: Spanish hospitals participating in PanGenEU, a pan-European multicentre case–control study, and their genetic counseling unit. Individuals at high-risk of PDAC were enrolled into a screening programme, consisting of Endoscopic ultrasound, computerised tomography, magnetic resonance imaging. Genetic testing of candidate genes was offered according to each patient’s risk.ResultsAmong 577 consecutive PDAC cases, recruited via PanGenEU, 36 (6%) had ⩾2 first-degree relative with PDAC: Familial pancreatic cancer (FPC). So far PanGen-Fam has recruited 42 high-risk PDAC families; 25 (60%) had FPC. Five index cases with cancer were positive for BRCA2 and one for BRCA1 germline mutations. In the second year of prospective PDAC screening, one neuroendocrine tumour and a high-grade dysplasia lesion suspicious of carcinoma were diagnosed among 41 high-risk individuals. Furthermore EUS detected chronic-pancreatitis-like parenchymal changes in 15 patients.Concluding statementThe identification and recruitment of PDAC high-risk families into the PanGen-Fam registry provides an opportunity to detect early onset cancer and precursor pancreatic cancer lesions at a potentially curative stage and to increase the knowledge of the natural history of the disease.     

Pancreatic cancer surgery: past,present, and future

The history of pancreatic cancer surgery, though fraught with failure and setbacks, is punctuated by periods of incremental progress dependent upon the state of the art and the mettle of the surgeons daring enough to attempt it. Surgical anesthesia and the aseptic techniques developed during the latter half of the 19^th century were instrumental in establishing a viable setting for pancreatic surgery to develop. Together, they allowed for bolder interventions and improved survival through the post-operative period. Surgical management began with palliative procedures to address biliary obstruction in advanced disease. By the turn of the century, surgical pioneers such as Alessandro Codivilla and Walther Kausch were demonstrating the technical feasibility of pancreatic head resections and applying principles learned from palliation to perform complicated anatomical reconstructions. Allen O. Whipple, the namesake of the pancreaticoduodenectomy (PD), was the first to take a systematic approach to refining the procedure. Perhaps his greatest contribution was sparking a renewed interest in the surgical management of periampullary cancers and engendering a community of surgeons who advanced the field through their collective efforts. Though the work of Whipple and his contemporaries legitimized PD as an accepted surgical option, it was the establishment of high-volume centers of excellence and a multidisciplinary approach in the later decades of the 20^th century that made it a viable surgical option. Today, pancreatic surgeons are experimenting with minimally invasive surgical techniques, expanding indications for resection, and investigating new methods for screening and early detection. In the future, the effective management of pancreatic cancer will depend upon our ability to reliably detect the earliest cancers and precursor lesions to allow for truly curative resections.     

Circulating tumor cells in pancreatic cancer patients: Methods of detection and clinical implications

The poor prognosis of pancreatic cancer patients is associated with the frequent and early dissemination of the disease, as well as late detection due to unspecific and late symptoms from the primary tumor. Pancreatic cancers frequently spread to the liver, lung and skeletal system, suggesting that pancreatic tumor cells must be able to intravasate and travel through the circulation to distant organs. Circulating tumor cells (CTCs) are tumor cells that have acquired the ability to enter the circulatory system; this cell population is ultimately responsible for the development of metastases in distant organs. Clinical studies have revealed that the presence of CTCs in blood is correlated with disease progression for other cancers, such as breast, colorectal and prostate cancer. However, as CTCs are extremely rare, both enrichment and sensitive methods of detection are required for their enumeration. This review highlights various enrichment procedures and methods for the detection of CTCs. Furthermore, we systematically review previously reported studies of the clinical relevance of CTC detection in pancreatic cancer patients. There is evidence that the presence of CTCs also correlates with an unfavorable outcome in pancreatic cancer patients. However, technical/methodological issues may explain why some studies only show a trend toward an association between CTC detection and disease progression. Larger studies, as well as characterization of the CTC population, are required to achieve further insight into the clinical implications of CTC detection in pancreatic cancer patients.     

Targeting of pancreatic and prostate cancer stem cell characteristics by Crambe crambe marine sponge extract

Cancer stem cells (CSCs) are suggested as reason for resistance of tumors toward conventional tumor therapy including pancreatic and advanced prostate cancer. New therapeutic agents are urgently needed for targeting of CSCs. Marine sponges harbor novel and undefined compounds with antineoplastic activity but their potential to eliminate CSC characteristics is not examined so far. We collected 10 marine sponges and one freshwater sponge by diving at the seaside and prepared crude methanolic extracts. The effect to established pancreatic and prostate CSC lines was evaluated by analysis of apoptosis, cell cycle, side population, colony and spheroid formation, migratory potential in vitro and tumorigenicity in vivo. While each sponge extract at a 1:10 dilution efficiently diminished viability, Crambe crambe marine sponge extract (CR) still strongly reduced viability of tumor cells at a dilution of 1:1,000 but was less toxic to normal fibroblasts and endothelial cells. CR inhibited self-renewal capacity, apoptosis resistance, and proliferation even in gemcitabine-selected pancreatic cancer cells with acquired therapy resistance and enhanced CSC characteristics. CR pretreatment of tumor cells diminished tumorigenicity of gemcitabine-resistant tumor cells in mice and totally abolished tumor take upon combination with gemcitabine. Our data suggest that CR contains substances, which render standard cancer therapy more effective by targeting of CSC characteristics. Isolation of bioactive metabolites from CR and evaluation in mice are required for development of new CSC-specific chemotherapeutic drugs from a marine sponge.     

The role of lncRNA MSC-AS1/miR-29b-3p axis-mediated CDK14 modulation in pancreatic cancer proliferation and Gemcitabine-induced apoptosis

Pancreatic ductal adenocarcinoma (PDAC) remains a leading cause of cancer-related death due to the failure of traditional therapies. In the present study, we attempted to construct a lncRNA-miRNA-mRNA network which may modulate PDAC cell proliferation and Gemcitabine-induced cell apoptosis starting from CDK14, a new member of the CDK family and an oncogene in many cancers. Based on TCGA data, a significant positive correlation was observed between lncRNA MSC-AS1 and CDK14. Moreover, MSC-AS1 expression was upregulated in PDAC tissues. Higher MSC-AS1 expression was correlated with poorer prognosis in patients with PDAC. MSC-AS1 knockdown in Panc-1 and BxPC-3 cells significantly inhibited the cell proliferation. Moreover, miR-29b-3p, which has been reported to act as a tumor suppressor, was predicted to bind to both MSC-AS1 and CDK14. Contrary to MSC-AS1, higher miR-29b-3p expression was correlated to better prognosis in patients with PDAC. In both PDAC cell lines, miR-29b-3p negatively regulated MSC-AS1 and CDK14. As confirmed using luciferase reporter gene and RIP assays, MSC-AS1 served as a ceRNA for miR-29b-3p to counteract miR-29b-mediated CDK14 repression. MSC-AS1 knockdown inhibited CDK14 protein levels and PDAC proliferation and enhanced gemcitabine-induced cell death and apoptosis while miR-29b-3p inhibition exerted an opposing effect; the effect of MSC-AS1 knockdown was partially attenuated by miR-29b-3p inhibition. Taken together, we demonstrated that MSC-AS1/miR-29b-3p axis modulates the cell proliferation and GEM-induced cell apoptosis in PDAC cell lines through CDK14. We provided a novel experimental basis for PDAC treatment from the perspective of lncRNA-miRNA-mRNA network.     

The immunological impact of preoperative chemoradiotherapy on the tumor microenvironment of pancreatic cancer

Several therapeutic regimens, including neoadjuvant chemoradiation therapy (NACRT), have been reported to serve as anticancer immune effectors. However, there remain insufficient data regarding the immune response after NACRT in pancreatic ductal adenocarcinoma (PDAC) patients. Data from 40 PDAC patients that underwent surgical resection after NACRT (NACRT group) and 30 PDAC patients that underwent upfront surgery (US group) were analyzed to examine alterations in immune cell counts/distribution using a multiplexed fluorescent immunohistochemistry system. All immune cells were more abundant in the cancer stroma than in the cancer cell nest regardless of preoperative therapy. Although the stromal counts of CD4+ T cells, CD20+ B cells, and Foxp3+ T cells in the NACRT group were drastically decreased in comparison with those of the US group, counts of these cell types in the cancer cell nest were not significantly different between the two groups. In contrast, CD204+ macrophage counts in the cancer stroma were similar between the NACRT and US groups, while those in the cancer cell nests were significantly reduced in the NACRT group. Following multivariate analysis, only a high CD204+ macrophage count in the cancer cell nest remained an independent predictor of shorter relapse-free survival (odds ratio = 2.37; P = .033). NACRT for PDAC decreased overall immune cell counts, but these changes were heterogeneous within the cancer cell nests and cancer stroma. The CD204+ macrophage count in the cancer cell nest is an independent predictor of early disease recurrence in PDAC patients after NACRT.