AIM:Pancreatic cancer (PC) has a poor prognosis and high mortality. Kruppel-like factor 9 (KLF9), a transcription factor, is aberrantly expressed in various neoplasms. The current study sought to analyze the functional role of KLF9 in the proliferation, invasion, and migration of PC cells.METHODS:The expression patterns of KLF9 and KIAA1522 in normal pancreatic cells (HPDE-C7) and PC cells (Panc 03.27, BxPc3, SW1990) were determined by real-time quantitative polymerase chain reaction and Western blot assay. After treatment of KLF9 overexpression, proliferation, invasion, and migration were evaluated by cell counting kit-8, 5-ethynyl-2'-deoxyuridine staining, and Transwell assays. The binding of KLF9 to the KIAA1522 promoter was analyzed by dual-luciferase assay and chromatin immunoprecipitation. The rescue experiment was conducted to analyze the role of KIAA1522.RESULTS:KLF9 was downregulated, while KIAA1522 was upregulated in PC cells. KLF9 overexpression mitigated the proliferation, invasion, and migration of PC cells. Enrichment of KLF9 led to inhibition of the KIAA1522 promoter and repressed KIAA1522 expression. KIAA1522 overexpression neutralized the inhibitory role of KLF9 in PC cell functions.CONCLUSION:KLF9 is enriched in the KIAA1522 promoter and negatively regulates KIAA1522 expression, thereby mitigating the proliferation, invasion, and migration of PC cells.

Nanoalbumin-paclitaxel (nab-paclitaxel) is a standard chemotherapy for pancreatic cancer but has shown limited efficacy. However, the mechanism through which circulating nab-paclitaxel passes through the tumour vascular endothelium has not been determined. In our study, a new nonradioactive and highly sensitive method for analysing nab-paclitaxel transcytosis was established. Based on these methods, we found that hypoxia significantly enhanced the autophagic degradation of CAV1 and therefore attenuated caveolae-mediated nab-paclitaxel transcytosis across endothelial cells (ECs). In a proof-of-concept experiment, higher levels of CAV1, accompanied by lower levels of LC3B, were observed in the vascular endothelium of pancreatic cancer tissues collected from patients who showed a good response to nab-paclitaxel compared with those from patients who showed a poor response to nab-paclitaxel. Furthermore, both in vivo and in vitro studies confirmed that suppressing the autophagic degradation of CAV1 via EC-specific ATG5 knockdown or hydroxychloroquine sulfate (HCQ) treatment significantly enhanced nab-paclitaxel translocation across the endothelial barrier into pancreatic cancer cells and amplified the inhibitory effect of nab-paclitaxel on pancreatic tumour growth. The stimulation of CAV1 expression by EC-specific overexpression of exogenous CAV1 or administration of gemcitabine hydrochloride (GE) had the same effect. These results demonstrated that suppressing CAV1 autophagic degradation is a novel translatable strategy for enhancing nab-paclitaxel chemotherapeutic activity in the treatment of pancreatic cancer.

Pancreatic cancer (PC), a gastrointestinal tract malignant tumor, has a poor prognosis due to early metastasis and limited response to chemotherapy. Therefore, identifying novel therapeutic approaches for PC is critical. Epithelial–mesenchymal transition (EMT) is known as the vital progress in PC development, we constructed the EMT-related prognosis model to screen out that FOXQ1 probably involving in the EMT regulation. FOXQ1 has been linked to the malignant process in a number of cancers. However, its function in PC is unknown. In our work, the expression of FOXQ1 was elevated in PC tissues, and a high level of FOXQ1 in PC was linked to patients’ poor prognosis. FOXQ1 overexpression promoted aerobic glycolysis and enhanced PC cell proliferation, tumor stemness, invasion, and metastasis. Whereas, FOXQ1 silencing showed the reverse effect. Furthermore, mechanistic studies indicated that FOXQ1 promotes LDHA transcription, and thus modulates aerobic glycolysis to enhance PC cell proliferation, tumor stemness, invasion, and metastasis by increasing LDHA expression. Therefore, these novel data suggest that FOXQ1 may be a possible therapeutic target in PC.

Background:A significant desmoplastic response, particularly in the fibroblasts, is a characteristic of pancreatic ductal adenocarcinoma (PDAC). Increasing evidence has shown that cancer-associated fibroblasts (CAFs) assist tumor development, invasion, and metastasis in PDAC. However, CAFs-derived molecular determinants that regulate the molecular mechanisms of PDAC have not been fully characterized.Methods:The expression of microRNA 125b-5p (miR-125b-5p) in Pancreas Cancer (PC) tissue and para-cancerous normal tissue was examined using Polymerase Chain Reaction (PCR). Cell counting kit-8 (CCK8), wound healing, and transwell experiments were utilized to assess the effect of miR-125b-5p. Using a cell luciferase activity test and bioinformatics, it was demonstrated that miR-125b-5p may bind to the 3'-untranslated region (3'-UTR) of the adenomatous polyposis coli (APC), thereby limiting the progression of pancreatic cancer.Results:PDAC cells are prompted to proliferate, undergo the epithelial-mesenchymal transition (EMT), and spread. Importantly, CAFs release exosomes into PDAC cells, which significantly increase the level of miR-125b-5p in those cells. Meanwhile, pancreatic cancer cell lines and PDAC tissues have considerably higher miR-125b-5p expression. MiR-125b-5p's elevated expression mechanically suppresses the expression of APC and accelerates the spread of pancreatic cancer.Conclusions:Exosomes released by CAFs promote PDAC growth, invasion, and metastasis. Exosomal miR-125b-5p inhibition offers an alternate strategy for combating the basic malady of PDAC.

Accumulating evidence has demonstrated the essential role of long noncoding RNAs (lncRNAs) in various types of human cancer, including pancreatic cancer (PC). However, the functions and regulatory mechanisms of nuclear receptor subfamily 2 group F member 1 antisense RNA 1 (NR2F1-AS1) that are responsible for its role in the malignant progression of PC cells remains to be investigated. In this study, the biological effects of NR2F1-AS1 and NR2F1 in PC were investigated by in vitro and in vivo experiments. The mechanisms of NR2F1-AS1 were monitored by bioinformatic predictive analysis and confirmatory experiments. Our results indicated that NR2F1-AS1 was overexpressed and positively correlated with poor survival in PC. Depletion of NR2F1-AS1 restrained PC cell proliferation, migration, invasion, and suppressed xenograft tumor growth and metastasis in vitro and in vivo. Mechanistic experiments suggested that NR2F1-AS1 positively regulated the neighboring NR2F1 gene, which subsequently activated AKT/mTOR signaling, resulting in the upregulation of hypoxia-inducible factor-1α (HIF-1α). Further investigations elucidated that NR2F1-AS1 expression was transcriptionally regulated by HIF-1α under hypoxia. These findings demonstrated that hypoxia-induced NR2F1-AS1 expression directly increased NR2F1 levels to promote PC cell proliferation, migration, and invasion by activating AKT/mTOR signaling. Together, these findings suggest that NR2F1-AS1 could be a prospective therapeutic target for PC.

目的 研究青藤碱对胆管癌细胞的抑制作用,并探究其可能的分子机制.方法 通过试剂盒检测青藤碱对胆管癌细胞caspase-3活性的影响,Western blot检测青藤碱对胆管癌细胞中增殖蛋白及PI3K/Akt通路的影响.应用PI3K/Akt抑制剂LY294002,探究PI3K/Akt通路在抗胆管癌中发挥的作用.通过裸鼠皮下成瘤实验,观察青藤碱对体内胆管癌恶性生物学效应的影响,并检测肿瘤组织中增殖、凋亡及PI3K/Akt相关蛋白表达的变化.结果 青藤碱可使胆管癌细胞中caspase-3活性增强.青藤碱可剂量依赖性地降低胆管癌细胞中增殖蛋白的表达,并抑制PI3K/Akt通路.PI3K/Akt特异性抑制剂LY294002可抑制胆管癌细胞的增殖蛋白表达,并可升高凋亡蛋白表达;与单用青藤碱比较,LY294002联合青藤碱可抑制胆管癌细胞增殖能力,并促进其凋亡;随着青藤碱剂量增加,其抑制荷瘤生长作用加强,并可降低胆管癌荷瘤中相关增殖蛋白与PI3K/Akt通路蛋白表达,升高凋亡蛋白表达.结论 青藤碱通过PI3K/Akt信号通路抑制胆管癌细胞增殖并促进凋亡,从而在体内外发挥良好的抗癌活性.

目的 探讨长链非编码RNA(LncRNA)Linc00858通过调控靶向小分子RNA?3126?5p(miR?3126?5p)影响肝癌细胞增殖、迁移和侵袭的作用机制.方法 通过实时荧光定量PCR(qRT?PCR)法检测Linc00858在肝癌组织、癌旁正常组织、人正常肝细胞LO2和人肝癌细胞系中的表达情况及两者相对关系.筛选出人肝癌细胞HUH?7和MHCC?97H作为研究对象,分别转染Linc00858过表达和干扰Linc00858表达的重组慢病毒,使用qRT?PCR测定转染效果,通过CCK?8实验、Transwell实验检测肿瘤细胞的增殖、迁移及侵袭能力,Western blot实验检测Linc00858对上皮?间质转化和细胞周期相关的蛋白表达水平的影响;生物信息学预测和双荧光素酶报告实验确定两者的结合关系.调整Linc00858的表达水平后,采用qRT?PCR法检测肝癌细胞中miR?3126?5p表达水平的变化,将miR?3126?5p mimics和miR?3126?5p inhibitor分别进行转染,通过上述方法再次检测肝癌细胞增殖、迁移和侵袭能力及相关蛋白表达情况.结果 Linc00858在肝癌组织和细胞中的表达量高于癌旁正常组织和LO2;过表达Linc00858后HUH?7细胞增殖、迁移及侵袭能力明显上升,细胞周期蛋白E1(cyclin E1)、周期素依赖性激酶2(CDK2)和波形蛋白(Vimentin)的表达明显上升,P27和钙粘附蛋白E(E?cadherin)的表达明显下降;沉默Linc00858可以抑制MCHH?97H细胞增殖、迁移及侵袭能力,cyclin E1、CDK2和Vimentin的表达明显下降,P27和E?cadherin的表达明显上升;Linc00858靶向调控miR?3126?5p的表达,miR?3126?5p mimics能明显逆转过表达Linc00858对HUH?7细胞的增殖、迁移及侵袭能力以及相关蛋白表达水平;miR?3126?5p inhibitor可以逆转沉默Linc00858对MHCC?97H细胞的增殖、迁移及侵袭能力以及相关蛋白表达水平.结论 Linc00858通过负向调控miR?3126?5p来促进肝癌细胞的增殖、侵袭和迁移.

Inflammatory molecules and exosomes are crucial for signal transduction between tumor-associated macrophages and tumor cells. IL-6, a key inflammatory molecule secreted by M2 macrophages after polarization, can mediate malignant progression of pancreatic cancer (PC). However, the functions and mechanisms of IL-6 and tumor-derived exosomes in tumor-associated macrophages and PC remain unclear. Transcriptome chip and quantitative reverse transcription PCR experiments indicated that FGD5-AS1 induced IL-6 and high FGD5-AS1 expression correlated with the poor prognosis in PC patients. RNA pulldown, mass spectrometry, and dual luciferase reporter assays were used to identify the mechanism of exosomal FGD5-AS1 in promoting PC progression and M2 macrophage polarization. FGD5-AS1 exerted cancer-promoting functions when co-cultured with M2 macrophages. PC-derived exosomal FGD5-AS1 stimulated M2 macrophage polarization by activating STAT3/NF-κB pathway. FGD5-AS1 interacts with p300, resulting in STAT3 acetylation, thus promoting nuclear localization and transcriptional activity of STAT3/NF-κB. These data indicated that PC cells generate FGD5-AS1-rich exosomes, which cause M2 macrophage polarization to promote the malignant behaviors of PC cells. Targeting exosomal FGD5-AS1 may provide a potential diagnosis and treatment strategy for PC.

Background: Pancreatic cancer is one of the most aggressive malignancies globally, with no improvement in the cure rates yet.Caveolin-2 (CAV2) has been repeatedly reported to play an important role in cellular transport and signalling and in exhibiting a pro-oncogenic response in a variety of tumours, although its specific action mechanisms in pancreatic cancer are not well documented. MiRNA is recognized as a therapeutic target for a variety of tumours, making it an important regulator of the Wnt/β-catenin signalling pathway. MiR-4723/Wnt7A constitutes an oncogenic signalling axis in pancreatic cancer by targeting and inhibiting Wnt7A through the activation of MiR4723, but its molecular action mechanism remains unexplored. Therefore, in the present study, we investigated the effect of CAV2 on the MiR-4723/Wnt7A pathway and its action mechanism. Methods: We employed TCGA, the GEO database for bioinformatics analysis, cell proliferation assay, wound healing assay, Transwell assay, colony-forming assay, qRT-PCR, and Western blotting to validate the cancer-promoting role of CAV2 in pancreatic cancer and to determine its potential target WNT7A. We then explored CAV2 as a positive regulator of the Wnt7A/β-catenin pathway through immunofluorescence assay, qRT-PCR, and Western blotting. Database analyses, CCK-8 and qRT-PCR revealed that MiR-4723 is an oncogene in pancreatic cancer. Luciferase assay and qRT-PCR revealed that MiR-4723 is a negative regulator of the Wnt7A/β-catenin pathway. To investigate the mechanism of CAV2 action on MiR-4723/Wnt7A, we detected the gene expression of CAV2 through qRT-PCR after MiR-4723 overexpression. Several genes related to endocytosis and epithelial-mesenchymal transition (EMT) were subsequently analysed through immunofluorescence, Western blotting, and qRT-PCR. Results: Overexpression of CAV2 promotes invasion, migration, cloning and metastasis of pancreatic cancer cells. Overexpression of MiR-4723 inhibits CAV2 expression. Here, we are the first to demonstrate that CAV2 exerts a pro-carcinogenic effect on pancreatic cancer through the activation of the Wnt7A/β-catenin signalling pathway. Conclusion: CAV2 can regulate the MiR-4723/Wnt7A signalling axis in pancreatic cancer cell lines by inhibiting endocytosis and promoting EMT, thereby fulfilling the mechanism pro-carcinogenic effects.

Pancreatic cancer (PC) is one of the most malignant types of cancer, and is characterized by early metastasis, limited response to chemotherapeutics, and poor prognosis. Therefore, there is an urgent need to explore new therapeutic strategies for PC treatment. Human rhomboid-like 2 (RHBDL2) is differentially expressed in cervical and breast cancer. However, the correlation between RHBDL2 and PC remains unclear. We found that RHBDL2 is highly expressed in human PC cells and tissues and is significantly associated with distant metastasis and poor survival of patients with PC. Gain- and loss-of-function assays indicated that RHBDL2 could accelerate PC cell proliferation and mobility in vitro and in vivo. The RNA-Seq results suggest that RHBDL2 may be involved in the activation of Notch signaling pathway. IMR-1 could restore the proliferation and metastatic capacity of PC cells mediated by RHBDL2. RHBDL2 interacted with and cleaved Notch1, resulting in the release of N1ICD. RHBDL2 decreased the ubiquitination level of N1ICD and collaborated with Ovarian tumor domain-containing 7B (OTUD7B) to stabilize N1ICD via the ubiquitin-proteasome pathway. RHBDL2 facilitated PC cell proliferation and mobility by stabilizing the N1ICD via the OTUD7B and activating the Notch signaling pathway. Thus, targeting this novel pathway may be a potential therapeutic strategy for PC.

Liver cancer (LC) is the leading cause for tumor-related death worldwide, and microRNAs (miRs) have been demonstrated to regulate the progression of LC. In the current study, the function of miR-660 in LC cells was investigated, and the results indicated that miR-660 was highly expressed in LC tissues and cells. This increased expression promoted LC cell proliferation and increased the percentage of S phase cells, while miR-660 knockdown inhibited cell proliferation and increased the percentage of G0/G1 phase cells. A Ser/Thr phosphatase protein phosphatase 2 regulatory subunit βα (PPP2R2A) was indicated as the target of miR-660, and miR-660 could inhibit PPP2R2A levels. The luciferase reporter assay suggested that miR-660 directly bound to the 3'-untranslated region of PPP2R2A. Additionally, it was revealed that miR-660 inhibited p21 expression and promoted cyclin D1 expression, confirming that miR-660 regulated LC cell proliferation by regulating cell cycle progression. The double knockdown of miR-660 and PPP2R2A promoted LC cell proliferation, suggesting that miR-660 promoted LC proliferation by targeting PPP2R2A.

目的:探讨细胞分裂周期相关蛋白7(cell division cycle-associated protein 7,CDCA7)对人胰腺癌细胞增殖、侵袭及迁移能力的影响,及其可能的作用机制.方法:利用癌症基因组图谱(The Cancer Genome Atlas,TCGA)和基因表达谱数据动态分析(Gene Expression Profiling Interactive Analysis,GEPIA)数据库分析胰腺癌组织及癌旁组织中CDCA7表达水平的差异,并采用实时荧光定量PCR和蛋白质印迹法分别检测CDCA7 mRNA和蛋白在人正常胰腺导管上皮细胞HPDE和人胰腺癌Bxpc-3、CFPAC-1、PANC-1、MIAPaCa-2、Capan2及SW1990细胞中的表达水平.构建干扰CDCA7基因表达的重组慢病毒,稳定转入PANC-1细胞,并分别采用实时荧光定量PCR和蛋白质印迹法检测干扰效率.干扰CDCA7基因表达后,分别采用CCK-8法和平板克隆实验检测对PANC-1细胞增殖能力的影响,细胞划痕愈合实验及Transwell小室法检测对PANC-1细胞迁移及侵袭能力的影响;进一步采用蛋白质印迹法检测干扰CDCA7表达后对上皮-间质转化相关蛋白波形蛋白(Vimentin)和E-钙黏蛋白(E-cadherin),以及细胞周期蛋白D1(cyclin D1)和cyclin E1表达水平的影响.通过生物信息学网站(STING和GEPIA)预测CDCA7与微型染色体维持蛋白3(minichromosome maintenance protein 3,MCM3)的关系,并进一步采用免疫共沉淀法检测CDCA7与MCM3的相互作用,采用蛋白质印迹法检测干扰CDCA7表达后MCM3蛋白表达水平的变化.结果:CDCA7在胰腺癌组织中的表达水平明显高于癌旁组织(P ＜0.05);CDCA7 mRNA及蛋白在胰腺癌PANC-1、MIA PaCa-2和SW1990细胞中的表达水平均明显高于人正常胰腺导管上皮细胞HPDE(P值均＜0.05).干扰CDCA7表达后,PANC-1细胞中CDCA7 mRNA和蛋白的表达水平明显下降(P值均＜0.05),PANC-1细胞的增殖、侵袭及迁移能力明显降低(P值均＜0.05);Vimentin、cyclin D1和cyclin E1蛋白的表达水平均明显下调,而E-cadherin蛋白的表达水平明显上调(P值均＜0.05).CDCA7与MCM3存在相互作用,且干扰CDCA7表达后MCM3蛋白的表达水平明显降低(P＜0.05).结论:CDCA7在部分胰腺癌细胞中高表达,干扰其表达可抑制胰腺癌PANC-1细胞的增殖、侵袭及迁移能力.

背景与目的:研究表明基因变异与胆囊结石生成密切相关.本研究通过病例对照研究探讨贵州地区汉族人群肥胖基因BChE单核苷酸多态性(SNP)与胆囊结石疾病发病风险的相关性,为其调控胆囊结石形成的分子机制提供研究基础.方法:选取171例贵州省汉族胆囊结石患者和125例健康对照者入组.从胆囊结石组和健康对照组的全血样本中提取全基因组DNA,以风险相关SNP位点ABCG8 rs11887534(D19H)作为阳性对照,采用TaqMan探针技术,对胆囊结石组和健康对照组肥胖相关基因BChE rs1126680、rs1803274进行基因分型.分别在纯合子模型及杂合子模型下利用Pearson x 2检验或者Fisher's确切分析进行SNP风险相关检验,并利用Logistic回归分析计算风险比,分析SNP位点与胆囊结石易感性的关系.结果:等位基因位点基因频率分布符合Hardy-Weinberg平衡定律(x2=0.641,P＞0.05),选择的样本具有群体代表性.胆囊结石患者及健康人群全血中高密度脂蛋白与低密度脂蛋白含量存在明显差异(均P＜0.05).TaqMan探针基因分型结果显示,3个标签SNP成功分型,并且每个标签SNP的分型成功率≥99.3％.阳性对照ABCG8 rs11887534杂合子CG(D19H)分型为胆囊结石风险相关SNP突变位点(P=0.006),肥胖相关基因BChE rs1803274杂合子CT与胆囊结石风险明显有关(P=1.312× 10-15),而肥胖相关基因BChE rs1126680为与胆囊结石疾病发病风险无关的突变位点(P=0.616).BChErs1803274杂合子CT分型与女性胆囊结石疾病的发病风险有较强的相关性(95％ CI=0.237～0.772,P=0.009).结论:在贵州地区汉族人群中,BChE基因SNP与胆囊结石发病风险有关,携带BChE基因rs1803274的个体尤其是女性,胆囊结石发病风险增高.

Background Prodigiosin (PG), a natural red pigment produced by numerous bacterial species, has been a eye-catching research point in recent years for its anticancer activity. However, the role of PG in the cancer biology of cholangiocarcinoma (CCA) remains vague. Methods The proliferation of CCA cells was detected by Cell Counting Kit-8(CCK-8), Colony formation assay and 5-ethynyl-2 '-deoxyuridine (EdU) assay. Cell apoptosis was evaluated by flow cytometry assay and western blot assay. The effects of PG or SNAREs on cell autophagy were measured by autophagy flux assay and western blot assay. Xenograft mouse models were used to assess the role of PG in CCA cells in vivo. Results PG could inhibit the proliferation and viability of CCA cells in a concentration- and time-dependent manner via suppressing the late stage of autophagy. Mechanistically, PG inhibits the fusion of autophagosomes and lysosomes by blocking STX17 and SNAP29, components of soluble N-ethyl-maleimide-sensitive factor attachment protein receptors (SNAREs)complex. When STX17 and SNAP29 were overexpressed, the inhibitory effect of PG on CCA cells autophagy was relieved. In addition, PG showed obvious inhibitory effects on cancer cell viability but no toxic effects on organs in xenotransplantation models. Conclusion Taken together, our results demonstrated that PG inhibits CCA cell proliferation via suppressing SNAREs-dependent autophagy, implying that PG could be a potential chemotherapy drug for advanced CCA.

Objective This study aimed to investigate the effects of propofol on cardiac function and miR-494 expression in rats with hepatic ischemia/reperfusion (I/R) injury. Methods Forty healthy adult male Sprague-Dawley rats were allocated to the sham operation group and three hepatic I/R injury groups. The I/R injury groups included I/R injury only (I/R group), treatment with propofol (propofol group), and treatment with propofol + overexpressed miR-494 (propofol+miR-494 group). Apoptosis of myocardial cells and changes in cardiac function indices, including left ventricular end-diastolic diameter, left ventricular end-systolic diameter, and left ventricular posterior wall thickness, as well as changes in miR-494, were monitored. Results The apoptotic rate of myocardial cells in the I/R group was higher, cardiac function was deteriorated, and miR-494 levels were elevated compared with the sham group. The apoptotic rate was lower, cardiac function was improved, and miR-494 levels were suppressed in the propofol group compared with the I/R group. The apoptotic rate was higher, cardiac function was deteriorated, and miR-494 levels were elevated in the propofol+miR-494 group compared with the propofol group. Conclusion Propofol plays a vital role in preventing myocardial cell apoptosis and improvement of cardiac function by suppressing miR-494 in a hepatic I/R injury rat model.

Spindle cell tumor is very rare. Herein, we report a case of retroperitoneal spindle cell tumor in a 52-year-old female. The patient first presented with a complaint of persistent pain in the right upper abdomen. In the follow-up, a CT scan was performed and showed a retroperitoneal soft tissue density mass measuring 11 cm in diameter. Then, a subsequent operation was performed, and we completely removed the tumor and partially invaded lesions. The tumor was histologically diagnosed as a spindle cell tumor. Therefore, it is imperative for us to enhance the understanding of this seldom found tumor. Surgery remains the best option for treatment.

Additional file 2: Table 2. The characteristics of the primers used in real-time PCR and plasmid sequence.

Purpose The tripartite motif-containing family member TRIM37 is involved in a number of important biological and pathological processes, and it has recently been shown to be an essential regulator of protein ubiquitination and a contributor to tumorigenesis. We previously showed that TRIM37 is overexpressed in and promotes the proliferation and invasion of pancreatic cancer (PC). Methods Sphere formation, flow cytometric, qRT-PCR, western blot, colony formation, EdU incorporation, mouse xenograft model, TUNEL and IHC assays were performed to detect the role of TRIM37 in stemness and chemoresistance of PC in vitro and in vivo. Bioinformatics analysis and dual-luciferase reporter assays were used to determine which intracellular pathways might mediate the effects of TRIM37 in PC cells. Immunofluorescent(IF) staining, co-immunoprecipitation(CO-IP), protein stability and ubiquitination assays were performed to investigate the relationship between TRIM37 and PTEN. Results TRIM37 modulates the ubiquitination and degradation of the tumor suppressor phosphatase and tensin homolog (PTEN), which negatively regulates the AKT–GSK-3β–β-catenin signaling pathway, thereby sustaining aberrant activation of PC cells. High expression of TRIM37 combined with low expression of PTEN correlates with poor survival of PC patients. Conclusions Collectively, our results suggest that inhibition of the TRIM37–AKT–GSK-3β–β-catenin axis may be a promising strategy for treatment of PC.

Cancer stem cells are the main reason for drug resistance and tumor relapse, and screening the targets for cancer stem cells is essential for tumor therapy. Here, we studied the role and regulatory mechanism of a G protein-coupled receptor named as G protein-coupled receptor 87 (GPR87) in the expansion of pancreatic ductal adenocarcinoma (PDA) stem cells. We found that GPR87 was an independent prognostic factor for PDA patients: patients with high GPR87 had a poor outcome. GPR87 significantly promoted the sphere formation ability, increased side population (SP) cell number, increased the expression of PDA stem cell markers, and increased the tumor initiation ability, suggesting that GPR87 promotes the expansion of PDA stem cells. Mechanism analysis suggested that signal transducer and activator of transcription 3 (STAT3) directly bound to the promoter of GPR87 to increase GPR87 expression; inversely, GPR87 also activated STAT3. Further analysis suggested that GPR87 activated Janus kinase 2 (JAK2), which can activate STAT3, inhibiting JAK2 activation in GPR87-overexpressing PDA cells, which significantly inhibited the expansion of PDA stem cells; these findings suggested that GPR87, JAK2, and STAT3 formed a positive feedback loop increasing PDA stem cell population. In PDA specimens, GPR87 expression is positively correlated with the phosphorylation level of STAT3 and JAK2, confirming GPR87 promoted PDA stem cell expansion through activating JAK2/STAT3. In summary, we found that GPR87, together with JAK2 and STAT3, formed a positive feedback loop to promote the expansion of PDA stem cells.