Sodium channel 1 subunit alpha SCNN1A exerts oncogenic function in pancreatic cancer via accelerating cellular growth and metastasis.

The identification of new diagnostic and therapeutic biomarkers might be helpful to understand molecular mechanism of cancer pathogenesis and develop anti-cancer targets. This study reported the alteration of Sodium channel 1 subunit alpha (SCNN1A) expression, its prognostic significance and biological roles in pancreatic cancer. Bioinformatics database was searched to explore the expression of SCNN1A in pancreatic cancer specimens and analysis results were further validated by qRT-PCR and Western blot assay. The correlation between SCNN1A expression and clinicopathological characteristics and its impact on survival outcome of pancreatic cancer patients were investigated using GEPIA database and Kaplan-Meier plotter. Loss- and gain-of-functional experiments in vitro were done to investigate the biological function of SCNN1A in pancreatic cancer. Bioinformatics analysis and validation experiment showed that SCNN1A was frequently overexpressed in pancreatic cancer specimens and cell lines (P < 0.001), and there were significant relevance between high SCNN1A expression and TP53 mutation (P < 0.05) as well as unfavorable prognosis of pancreatic cancer patients (HR for overall survival: 1.9, P = 0.003 and HR for disease-free survival: 1.7, P = 0.014). The silencing of SCNN1A suppressed cell proliferation, migration and invasion and induced cell apoptosis (P < 0.05), while its overexpression promoted aggressive phenotypes of pancreatic cancer cells in vitro (P < 0.05). SCNN1A possessed oncogenic function and its dysregulation could be implicated in the development and metastasis of pancreatic cancer.

A combination of circulating tumor cells and CA199 improves the diagnosis of pancreatic cancer.

BACKGROUND: Early diagnosis of pancreatic ductal adenocarcinoma (PDAC) is difficult due to the lack of effective screening tests. CA199, the standard biomarker for PDAC management, is not sufficiently reliable for early diagnosis. This prospective study aimed to evaluate whether circulating tumor cells (CTCs) could complement or perform better than CA199 in determining PDAC. METHODS: A total of 168 blood samples were collected from 80 patients with PDAC, 32 patients with acute pancreatitis, 22 patients with benign pancreatic masses, and 34 healthy donors. CTCs were detected by a novel system combining negative enrichment with immunostaining and fluorescence in situ hybridization (NE-imFISH). Next, ROC curves and AUC analyses were conducted to assess diagnostic abilities of CA199, CTCs, and the combination of the two biomarkers in PDAC. RESULTS: CTCs were stained as CD45-/DAPI+/CEP8 ≥3. With 2 CTCs/3.2 ml as the cut-off value, the sensitivity/specificity of the CTC number was 0.76/0.94, which was comparable to that of CA199 (0.78/0.83; Delong test p = 0.3360). Improved performance was achieved through a logistic regression model integrating CA199 and CTC number (AUCCTC+CA199  = 0.95, AUCCA199  = 0.80, AUCCTC number  = 0.85; Delong test p vs . CA199  < 0.0001 and p vs . CTC number  = 0.0002). CTC subtype was inferior to CTC number as a diagnostic marker (AUCCTC subtype  = 0.73; Delong test p vs . CTC number  < 0.0001). CONCLUSION: The dual-marker panel consisting of CA199 and CTC number can significantly improve upon the diagnostic performance of CA199 alone, highlighting the promising clinical utilization as an effective strategy for PDAC surveillance.

Malignant transformation of hepatic endometriosis: a case report and literature review.

BACKGROUND: Extrapelvic endometriosis is defined as the presence of ectopic endometrial tissue in structures outside the pelvis. Although extra-pelvic endometriosis is generally considered benign conditions, malignant potential within endometriotic foci occurs even after definitive surgery. Malignant transformation of hepatic endometriosis is extremely rare. Preoperative diagnosis of this cancer is difficult, and no guidelines on the optimal management currently exist. Here, we present a case report of malignant transformation of hepatic endometriosis and a brief literature review to highlight the current knowledge of the prevalence, clinical features, diagnosis, and management of this condition. CASE PRESENTATION: A 50-year-old woman with a 2-year duration of progressive right upper quadrant abdominal pain was admitted to the hospital. She underwent hysterectomy and bilateral salpingo-oophorectomy for benign conditions 4 years prior. Tumor markers demonstrated elevated carbohydrate antigen (CA)-199 112U/mL (normal range: 0-35U/mL) only. Radiological imaging suggested the presence of a 10.7 × 7.7-cm mass in the right lobe of the liver extending to the diaphragm. The intraoperative frozen sections suggested malignant tumor. Right hepatectomy with infiltrating diaphragm resection was performed. The final pathology with immunohistochemistry staining confirmed endometrioid adenocarcinoma in the liver originating from preexisting hepatic endometriosis. After the multidisciplinary team meeting, the consensus was surgery followed by adjuvant chemotherapy. To our knowledge, this is the first case of Chinese woman of a malignant liver tumor originating from endometriosis ever reported by reviewing the current English medical literature. CONCLUSION: Though rare, extrapelvic endometriosis-associated cancers should be considered as differentiated diagnosis even after hysterectomy and bilateral salpingo-oophorectomy. This case highlights the importance of collaborative efforts across multiple disciplines for accurate diagnosis and appropriate treatment of malignant transformation of hepatic endometriosis.

Integrated analysis identifies a pathway-related competing endogenous RNA network in the progression of pancreatic cancer.

BACKGROUND: It is well acknowledged that cancer-related pathways play pivotal roles in the progression of pancreatic cancer (PC). Employing Integrated analysis, we aim to identify the pathway-related ceRNA network associated with PC progression. METHODS: We divided eight GEO datasets into three groups according to their platform, and combined TCGA and GTEx databases as a group. Additionally, we screened out the differentially expressed genes (DEGs) and performed functional enrichment analysis in each group, and recognized the top hub genes in the most enriched pathway. Furthermore, the upstream of miRNAs and lncRNAs were predicted and validated according to their expression and prognostic roles. Finally, the co-expression analysis was applied to identify a pathway-related ceRNA network in the progression of PC. RESULTS: A total of 51 significant pathways that common enriched in all groups were spotted. Enrichment analysis indicated that pathway in cancer was greatly linked with tumor formation and progression. Next, the top 20 hug genes in this pathway were recognized, and stepwise prediction and validation from mRNA to lncRNA, including 11 hub genes, 4 key miRNAs, and 2 key lncRNAs, were applied to identify a meaningful ceRNA network according to ceRNA rules. Ultimately, we identified the PVT1/miR-20b/CCND1 axis as a promising pathway-related ceRNA axis in the progression of PC. CONCLUSION: Overall, we elucidate the pathway-related ceRNA regulatory network of PVT1/miR-20b/CCND1 in the progression of PC, which can be considered as therapeutic targets and encouraging prognostic biomarkers for PC.

RAC1-mediated integrin alpha-6 expression in E-cadherin-deficient gastric cancer cells promotes interactions with the stroma and peritoneal dissemination.

Diffuse-type gastric cancer (DGC) is a subtype of gastric cancer that is prone to peritoneal dissemination, with poor patient prognosis. Although intercellular adhesion loss between cancer cells is a major characteristic of DGCs, the mechanism underlying the alteration in cell-to-extracellular matrix (ECM) adhesion is unclear. We investigated how DGCs progress and cause peritoneal dissemination through interactions between DGC cells and the tumour microenvironment (TME). P53 knockout and KRASG12V-expressing (GAN-KP) cells and Cdh1-deleted GAN-KP (GAN-KPC) cells were orthotopically transplanted into the gastric wall to mimic peritoneal dissemination. The GAN-KPC tumour morphology was similar to that of human DGCs containing abundant stroma. RNA sequencing revealed that pathways related to Rho GTPases and integrin-ECM interactions were specifically increased in GAN-KPC cells compared with GAN-KP cells. Notably, we found that Rac Family Small GTPase 1 (RAC1) induces Integrin Subunit Alpha 6 (ITGA6) trafficking, leading to its enrichment on the GC cell membrane. Fibroblasts activate the FAK/AKT pathway in GC cells by mediating extracellular matrix (ECM)-Itga6 interactions, exacerbating the malignant phenotype. In turn, GC cells induce abnormal expression of fibroblast collagen and its transformation into cancer-associated fibroblasts (CAFs), resulting in DGC-like subtypes. These findings indicate that Cdh1 gene loss leads to abnormal expression and changes in the subcellular localization of ITGA6 through RAC1 signalling. The latter, through interactions with CAFs, allows for peritoneal dissemination.

Mesothelial cells with mesenchymal features enhance peritoneal dissemination by forming a protumorigenic microenvironment.

Malignant ascites accompanied by peritoneal dissemination contain various factors and cell populations as well as cancer cells; however, how the tumor microenvironment is shaped in ascites remains unclear. Single-cell proteomic profiling and a comprehensive proteomic analysis are conducted to comprehensively characterize malignant ascites. Here, we find defects in immune effectors along with immunosuppressive cell accumulation in ascites of patients with gastric cancer (GC) and identify five distinct subpopulations of CD45(-)/EpCAM(-) cells. Mesothelial cells with mesenchymal features in CD45(-)/EpCAM(-) cells are the predominant source of chemokines involved in immunosuppressive myeloid cell (IMC) recruitment. Moreover, mesothelial-mesenchymal transition (MMT)-induced mesothelial cells strongly express extracellular matrix (ECM)-related genes, including tenascin-C (TNC), enhancing metastatic colonization. These findings highlight the definite roles of the mesenchymal cell population in the development of a protumorigenic microenvironment to promote peritoneal dissemination.

Non-coding RNA in tumor-infiltrating regulatory T cells formation and associated immunotherapy.

Cancer immunotherapy has exhibited promising antitumor effects in various tumors. Infiltrated regulatory T cells (Tregs) in the tumor microenvironment (TME) restrict protective immune surveillance, impede effective antitumor immune responses, and contribute to the formation of an immunosuppressive microenvironment. Selective depletion or functional attenuation of tumor-infiltrating Tregs, while eliciting effective T-cell responses, represents a potential approach for anti-tumor immunity. Furthermore, it does not disrupt the Treg-dependent immune homeostasis in healthy organs and does not induce autoimmunity. Yet, the shared cell surface molecules and signaling pathways between Tregs and multiple immune cell types pose challenges in this process. Noncoding RNAs (ncRNAs), including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), regulate both cancer and immune cells and thus can potentially improve antitumor responses. Here, we review recent advances in research of tumor-infiltrating Tregs, with a focus on the functional roles of immune checkpoint and inhibitory Tregs receptors and the regulatory mechanisms of ncRNAs in Treg plasticity and functionality.

Downregulation of 15-PGDH enhances MASH-HCC development via fatty acid-induced T-cell exhaustion.

Background & Aims: Hepatocellular carcinoma (HCC) mainly develops from chronic hepatitis. Metabolic dysfunction-associated steatohepatitis (MASH) has gradually become the main pathogenic factor for HCC given the rising incidence of obesity and metabolic diseases. 15-Hydroxyprostaglandin dehydrogenase (15-PGDH) degrades prostaglandin 2 (PGE2), which is known to exacerbate inflammatory responses. However, the role of PGE2 accumulation caused by 15-PGDH downregulation in the development of MASH-HCC has not been determined. Methods: We utilised the steric animal model to establish a MASH-HCC model using wild-type and 15-Pgdh+/- mice to assess the significance of PGE2 accumulation in the development of MASH-HCC. Additionally, we analysed clinical samples obtained from patients with MASH-HCC. Results: PGE2 accumulation in the tumour microenvironment induced the production of reactive oxygen species in macrophages and the expression of cell growth-related genes and antiapoptotic genes. Conversely, the downregulation of fatty acid metabolism in the background liver promoted lipid accumulation in the tumour microenvironment, causing a decrease in mitochondrial membrane potential and CD8+ T-cell exhaustion, which led to enhanced development of MASH-HCC. Conclusions: 15-PGDH downregulation inactivates immune surveillance by promoting the proliferation of exhausted effector T cells, which enhances hepatocyte survival and proliferation and leads to the development of MASH-HCC. Impact and implications: The suppression of PGE2-related inflammation and subsequent lipid accumulation leads to a reduction in the severity of MASH and inhibition of subsequent progression toward MASH-HCC.

Cancer-associated fibroblasts reuse cancer-derived lactate to maintain a fibrotic and immunosuppressive microenvironment in pancreatic cancer.

Glycolysis is highly enhanced in pancreatic ductal adenocarcinoma (PDAC) cells; thus, glucose restrictions are imposed on nontumor cells in the PDAC tumor microenvironment (TME). However, little is known about how such glucose competition alters metabolism and confers phenotypic changes in stromal cells in the TME. Here, we report that cancer-associated fibroblasts (CAFs) with restricted glucose availability utilize lactate from glycolysis-enhanced cancer cells as a fuel and exert immunosuppressive activity in the PDAC TME. The expression of lactate dehydrogenase A (LDHA), which regulates lactate production, was a poor prognostic factor for patients with PDAC, and LDHA depletion suppressed tumor growth in a CAF-rich murine PDAC model. Coculture of CAFs with PDAC cells revealed that most of the glucose was taken up by the tumor cells and that CAFs consumed lactate via monocarboxylate transporter 1 to enhance proliferation through the TCA cycle. Moreover, lactate-stimulated CAFs upregulated IL-6 expression and suppressed cytotoxic immune cell activity synergistically with lactate. Finally, the LDHA inhibitor FX11 reduced tumor growth and improved antitumor immunity in CAF-rich PDAC tumors. Our study provides insight regarding the crosstalk among tumor cells, CAFs, and immune cells mediated by lactate and offers therapeutic strategies for targeting LDHA enzymatic activity in PDAC cells.

Pancreaticojejunostomy Conducive to Biological Healing in Minimally Invasive Pancreaticoduodenectomy.

BACKGROUND: Pancreaticojejunostomy, an independent risk factor for pancreatic fistula, is the cause of several postoperative complications of pancreaticoduodenectomy. As suturing in minimally invasive surgery is difficult to perform, more simplified methods are needed to guarantee a safe pancreatic anastomosis. The concept of "biological healing" proposed in recent years has changed the conventional understanding of the anastomosis, which recommends rich blood supply, low tension, and loose sutures in the reconstruction of the pancreatic outflow tract. METHODS: A literature search was conducted in PubMed for articles on pancreaticojejunostomy published between January 2014 and December 2021. After following a due selection process, several techniques developed in accordance with the concept of biological healing that were found suitable for minimally invasive surgery and their related clinical outcomes were described in this review. RESULTS: The incidence of clinically relevant pancreatic fistula associated with the presented techniques did not exceed 15.9%, indicating superior results compared to Cattell-Warren double-layer duct-to-mucosa anastomosis (incidence: approximately 20%). The features and drawbacks of these approaches have been enumerated from the viewpoint of biological healing. CONCLUSIONS: This review described several modified pancreaticojejunostomy techniques with the advantages of a simplified procedure and a lower incidence of pancreatic fistula. Surgeons can choose to apply them in clinical practice to improve patient prognosis.

A necroptosis-related gene signature for predicting prognosis, immune landscape, and drug sensitivity in hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) remains a growing threat to global health. Necroptosis is a newly discovered form of cell necrosis that plays a vital role in cancer development. Thus, we conducted this study to identify a predictive signature of HCC based on necroptosis-related genes. METHODS: The tumor samples in the liver hepatocellular carcinoma (LIHC) cohort from The Cancer Genome Atlas (TCGA) database were subtyped using the consensus clustering algorithm. Univariate Cox regression and LASSO-Cox analysis were performed to identify a gene signature from genes differentially expressed between tumor clusters. Then, we integrated the TNM stage and the prognostic model to build a nomogram. The gene signature and the nomogram were externally validated in the GSE14520 cohort from the Gene Expression Omnibus (GEO) and the LIRP-JP cohort from the International Cancer Genome Consortium (ICGC). Evaluations of predictive performance evaluations were conducted using Kaplan-Meier plots, time-dependent receiver operating characteristic curves, principal component analyses, concordance indices, and decision curve analyses. The tumor microenvironment was estimated using eight published methods. Finally, we forecasted the sensitivity of HCC patients to immunotherapy and chemotherapy based on this gene signature. RESULTS: We identified two necroptosis-related clusters and a 10-gene signature (MTMR2, CDCA8, S100A9, ANXA10, G6PD, SLC1A5, SLC2A1, SPP1, PLOD2, and MMP1). The gene signature and the nomogram had good predictive ability in the TCGA, ICGC, and GEO cohorts. The risk score was positively associated with the levels of necroptosis and immune cell infiltrations (especially of immunosuppressive cells). The high-risk group could benefit more from immunotherapy and some chemotherapeutics than the low-risk group. CONCLUSION: The necroptosis-related gene signature provides a new method for the risk stratification and treatment optimization of HCC. The nomogram can further improve predictive accuracy.

Erratum: IRS-1 regulates proliferation, invasion and metastasis of pancreatic cancer cells through MAPK and PI3K signaling pathways.

[This corrects the article on p. 5185 in vol. 11, PMID: 31949598.].

Prognostic Value and Correlation With Tumor Immune Infiltration of a Novel Metabolism-Related Gene Signature in Pancreatic Cancer.

BACKGROUND: Energy metabolism has been considered as one of the novel features of neoplasms. This study aimed to establish the prognostic signature for pancreatic cancer (PC) based on metabolism-related genes (MRGs). METHODS: We obtained MRGs from the Molecular Signatures Database (MSigDB) and gene sequence data in the Cancer Genome Atlas (TCGA) databases. Then, differentially expressed MRGs (DE-MRGs) were identified utilizing the R software. We built the prognostic model via multivariate Cox regression. Moreover, external validation of the prognostic signature was also performed. Nomogram was created to predict the overall survival (OS). Next, this study analyzed the prognostic value, clinical relationship, and metabolism-related signaling pathways of the prognostic signature. The role in tumor infiltration was further evaluated. Eventually, the expression level of the three MRGs along with the function of NT5E was validated. RESULTS: Twenty-two MRGs were chosen, eight of which were identified to be most significantly correlated with the prognosis of PC. Meanwhile, a 3-MRG prognostic signature was established, and we verified this prognostic model in two separate external cohorts. What is more, the nomogram was used to predict 1-/2-/3-year OS of PC patients. In addition, the immune cell infiltration and expression of immune checkpoint were significantly influenced by the risk score. Finally, three MRGs were highly expressed in PC cell lines, and NT5E was associated with the proliferation and migration ability of PC. CONCLUSION: To sum up, the study established and validated a 3-MRG prognostic signature for PC, and the signature could be utilized to predict the prognosis and assist the individualized clinical management of patients with PC.

The miR-1224-5p/ELF3 Axis Regulates Malignant Behaviors of Pancreatic Cancer via PI3K/AKT/Notch Signaling Pathways.

PURPOSE: Aberrant expression of microRNAs contributes to the progression of pancreatic cancer by targeting downstream genes. A novel regulatory axis, miR-1224-5p/ELF3, was identified by bioinformatic analysis and experimental verification. Studies of the underlying molecular mechanisms behind this axis lead to a better understanding of the development of pancreatic cancer. MATERIALS AND METHODS: The differential expression of miR-1224-5p and ELF3 was verified based on Gene Expression Omnibus (GEO) datasets and clinical samples. The relationship between miR-1224-5p and ELF3 was demonstrated by luciferase assay and Western blot. The related signaling pathways of the miR-1224-5p/ELF3 axis in pancreatic cancer were investigated by gene set enrichment analysis (GSEA) and verified by Western blot. An analysis between ELF3 expression and immune infiltration was performed. Cellular and animal experiments were utilized to explore the effects of miR-1224-5p and ELF3 in pancreatic cancer. RESULTS: Suppressed expression of miR-1224-5p in pancreatic tumor tissues and cancer cells was identified first. Furthermore, miR-1224-5p is correlated with clinicopathological features, and decreased expression of miR-1224-5p indicates poor prognosis. miR-1224-5p serves as a tumor suppressor and inhibits malignant behaviors of pancreatic cancer based on in vivo and in vitro assays. The putative target gene ELF3 was predicted by bioinformatic analysis and confirmed by dual-luciferase reporter assay. Overexpression of ELF3 can improve the malignant behaviors of pancreatic cancer and demonstrates poor prognosis and advanced clinical stage. The inhibitory role of miR-1224-5p in pancreatic cancer is manifested by its direct targeting of ELF3. A negative correlation between ELF3 expression and immune cell infiltration was identified, suggesting an immunosuppressive state resulting from ELF3 overexpression. The PI3K/AKT/Notch signaling pathways and epithelial-to-mesenchymal transition (EMT) are important underlying mechanisms. CONCLUSION: The miR-1224-5p/ELF3 axis may serve as a new diagnostic, therapeutic, and prognostic biomarker in pancreatic cancer. The related PI3K/AKT/Notch/EMT signaling pathways greatly promote the elucidation of the progression of pancreatic cancer.

TSPAN1 upregulates MMP2 to promote pancreatic cancer cell migration and invasion via PLCγ.

Pancreatic cancer (PC), a malignancy of the digestive system, has one of the highest rates of metastasis and mortality. It is characterized by the detachment, migration, implantation and infiltration of tumor cells to form metastases or recurrent foci. Tetraspanin 1 (TSPAN1), a novel member of the TSPAN superfamily, is highly expressed in many types of cancer, including gastric, colon, liver and esophageal cancer. It has also been associated with lymph node metastasis, tumor recurrence and metastasis. However, the role of TSPAN1 in PC has not been fully elucidated. The aim of the present study was to determine the expression of TSPAN1 in human PC tissue samples and cell lines. Additionally, the functions of TSPAN1 in PC cell migration and invasion were assessed. The protein and gene expression of TSPAN1 was analyzed in clinical PC tissue samples and human PC cell lines (SW1990, BxPC3, Capan1 and PANC­1) via immunohistochemistry, reverse transcription­quantitative polymerase chain reaction and western blotting. The effect of TSPAN1 downregulation and overexpression in PC cells, via transfection with siRNA and pLNCX­TSPAN1­cDNA recombinant plasmid, respectively, on cell invasion and migration were assessed. Additionally, the mRNA expression of matrix metalloproteinase (MMP2) and MMP9 were determined. In clinical PC tissue samples, the expression of TSPAN1 was markedly increased when compared with normal pancreatic tissue samples. TSPAN1 was also highly expressed in PC cell lines compared with HPDE, a normal pancreatic cell line. Transfection with siRNA targeting TSPAN1 in PC cell lines significantly suppressed PC cell migration and invasion, and downregulated the expression of MMP2. However, there was no effect on MMP9. Consistently, PC cell migration and invasion together with MMP2 mRNA expression were markedly increased following TSPAN1 ectopic overexpression. The present study utilized small interfering RNAs (siRNA) targeted to phospholipase Cγ (PLCγ) to demonstrate that TSPAN1 siRNA suppressed PC cell migration and invasion, and MMP2 mRNA expression by blocking the translocation and phosphorylation of PLCγ. The results of the present study revealed that TSPAN1 has an important function in human PC cell migration and invasion by modulating MMP2 expression via PLCγ. Thus, the results indicate that the silencing of TSPAN1 may be a potential therapeutic target for the treatment of PC.

Differential expression profiles of microRNAs in highly and weakly invasive/metastatic pancreatic cancer cells.

Pancreatic cancer is the eighth-leading cause of cancer-associated mortality worldwide. To date, the cellular and molecular mechanisms associated with the invasion and metastasis of pancreatic cancer remain unclear. To examine these mechanisms, a microRNA (miRNA/miR) microarray with 1,965 genes was hybridized with labeled miRNA probes from invasive PC-1.0 and non-invasive PC-1 cells for molecular profiling analysis. In addition, reverse transcription quantitative-polymerase chain reaction (RT-qPCR) was utilized to validate the microarray results. Online miRNA target prediction algorithms online were used to predict the target genes of the differentially expressed miRNAs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) term enrichment analysis were performed for the potential targets of the differentially expressed miRNAs. The results demonstrated that 54 miRNAs were differentially expressed, of which 33 were upregulated and 21 were downregulated in the PC-1.0 cell line compared with the PC-1 cell line. A total of 6 upregulated miRNAs (miR-31, -34a, -181a, -181b, -193a-3p, and -193b) and 4 downregulated miRNAs (miR-221, -222, -484, and -502-3p) were selected from these 54 miRNAs and validated by RT-qPCR. The differentially expressed miRNAs were further validated by RT-qPCR in the human pancreatic cancer cell lines AsPC-1 (highly invasive) and CAPAN-2 (less invasive). The results revealed that 2 upregulated miRNAs (miR-34a and -193a-3p) and 4 downregulated miRNAs (miR-221, -222, -484, and -502-3p) exhibited a consistent expression pattern between the PC-1.0/PC-1 and AsPC-1/CAPAN-2 pancreatic cancer cells. The GO and KEGG enrichment analysis indicated that the mRNAs potentially targeted by miRNAs were involved in a range of biological functions. These results suggest that different miRNA expression profiles occur between highly and weakly invasive and metastatic pancreatic cancer cell lines, and may affect a variety of biological functions in pancreatic cancer.

IRS-1 regulates proliferation, invasion and metastasis of pancreatic cancer cells through MAPK and PI3K signaling pathways.

PC is one of the deadliest cancers, with unexpectedly high mortality. The main reason for poor prognosis is the high likelihood of invasion and metastasis of pancreatic cancer cells. Mechanism of exceptional protein phosphorylation that regulates cell invasion and metastasis in pancreatic cancer remain unclear. In our previous studies, we used high-throughput phosphorylation array to test two pancreatic cancer cell lines (PC-1 cells with a low potential, and PC-1.0 cells with a high potential, for invasion and metastasis). We noted that a total of 57 proteinsrevealed a differential expression (fold change 2.0). We supposed that insulin receptor substrate-1 (IRS-1) may play a significant role in pancreatic cancer invasion and metastasis. In this study, similar phosphorylation and protein expression levels together with morphological and functional characteristics were observed in PC-1.0 hamster pancreatic cancer cells and Aspc-1 human pancreatic cancer cells (similar to PC-1.0 in features) transiently transfected with IRS-1 siRNA. Our results indicated that proliferation, invasion and metastasis were reduced in both hamster and human pancreatic cancer cells. IRS-1 was found to regulate the target proteins involved in MAPK and PI3K signaling pathways, which include MEK1, MEK2 and AKT, at the protein and phosphorylation level. Low expression of IRS-1 in pancreatic cancer cells inhibited cell proliferation by targeting MEK1 and AKT, while inhibiting invasion and metastasis by targeting MEK2. Moreover, our results demonstrate that IRS-1 protein and phosphorylation expression levels are negatively controlled by LAR (protein tyrosine phosphatase, receptor type, F). LAR inhibited proliferation, invasion and metastasis of pancreatic cancer cells via a direct decrease of IRS-1 protein and phosphorylation expression levels. In summary, we demonstrate that IRS-1 regulates proliferation, invasion and metastasis of pancreatic cancer cells, and provides a new biomarker in an effort to develop novel therapeutic drug targets for pancreatic cancer treatment.

MicroRNA-221 induces autophagy through suppressing HDAC6 expression and promoting apoptosis in pancreatic cancer.

Pancreatic cancer is an aggressive type of cancer with a poor prognosis, short survival rate and high mortality. Therefore, understanding the molecular mechanism underlying the aggressive growth of pancreatic cancer is of importance. An increasing number of studies suggest that numerous microRNAs (miRNAs/miRs) are associated with the tumorigenesis, progression and prognosis of tumors. In a recent study by the present authors, it was revealed that the expression of miR-221 was significantly downregulated in highly aggressive pancreatic cancer cells compared with weakly aggressive pancreatic cancer cells. In addition, miR-221 has been suggested as a novel tumor-associated miRNA, as it is involved in apoptosis, invasion, metastasis and autophagy of tumor cells. However, the function of miR-221 in pancreatic cancer remains yet to be investigated. In the present study, it was revealed that transfection with miR-221 mimic was able to significantly induce apoptosis and autophagy in pancreatic cancer cells compared with the negative control. The protein deacetylase histone deacetylase-6 (HDAC6) has emerged to be an important component in the cellular management of protein aggregates. Studies suggest that HDAC6 serves a function in the clearance of aggresomes, thereby implying a functional association between HDAC6 and autophagy. In the present study, it was revealed that transfection with miR-221 mimic was able to suppress the protein expression of HDAC6 in pancreatic cancer cells compared with the negative control. Immunofluorescence data suggested that the inhibition of HDAC6 was able to induce autophagy in pancreatic cancer cells. Additionally, the results of the present study suggest that the downregulation of miR-221 expression may serve an oncogenic function in the apoptosis and autophagy of pancreatic cancer cells by inducing the expression of HDAC6.

UCA1 Regulates the Growth and Metastasis of Pancreatic Cancer by Sponging miR-135a.

Pancreatic cancer (PC) is a devastating malignant disease with a poor prognosis. This study aimed to investigate the role of urothelial carcinoma associated 1 (UCA1) in the progression of PC. Our results revealed that long noncoding RNA (lncRNA) UCA1 was overexpressed in PC tissues compared with adjacent histologically normal tissues. A downregulated level of UCA1 was also detected in five human PC cell lines (SW1990, BxPC-3, MiaPaCa-2, PANC-1, and CAPAN-1) compared with normal pancreatic duct epithelial HPDE cells. The proliferation of PC cells was inhibited after UCA1 was suppressed by a lentiviral vector. The cell apoptosis rate was largely promoted by downregulating UCA1. Further research revealed that microRNA (miRNA)-135a is a direct target of UCA1. The expression of miR-135a was decreased in PC tissues and cell lines compared with control groups. In addition, the decreased level of miR-135a was elevated by adding miR-135a mimic in SW1990 cells transfected with lncRNA UCA1. Similarly, an upregulated level of miR-135a was downregulated by adding miR-135a inhibitor in SW1990 cells transfected with UCA1 siRNA. Luciferase activity assay further confirmed the targeting relationship between UCA1 and miR-135a. Moreover, miR-135a reversed the effect of UCA1 on cell apoptosis rate and cell viability in SW1990 cells. The migration and invasion capacities of PC cells were suppressed by UCA1. siRNA was then enhanced by the miR-135a inhibitor. In vivo, UCA1 siRNA effectively suppressed tumor growth and the expression of migration markers. Taken together, our research revealed that UCA1 works as an oncogene by targeting miR-135a. The UCA1-miR-135a pathway regulated the growth and metastasis of PC, providing new insight in the treatment of PC.