BackgroundA major challenge in the treatment of pancreatic ductal adenocarcinoma is the failure of chemotherapy, which is likely due to the presence of the cancer stem cells (CSCs).ObjectiveTo identify side population (SP) cells and characterize s-like properties in human pancreatic cancer cell lines (h-PCCLs) and to exploit the efficacy of concomitant targeting of multiple key transcription factors governing the stemness of pancreatic CSCs in suppressing CSC-like phenotypes.MethodsFlow cytometry and Hoechst 33342 DNA-binding dye efflux assay were used to sort SP and non-SP (NSP) cells from three h-PCCLs: PANC-1, SW1990, and BxPc-3. The self-renewal ability, invasiveness, migration and drug resistance of SP cells were evaluated. Expression of CSC marker genes was analyzed. Tumorigenicity was assessed using a xenograft model in nude mice. Effects of a complex decoy oligonucleotide (cdODN-SCO) designed to simultaneously targeting Sox2, Oct4 and c-Myc were assessed.ResultsCSCs were enriched in the side proportion (SP) cells contained in the h-PCCLs and they possessed aggressive growth, invasion, migration and drug-resistance properties, compared with NSP cells. SP cells overexpressed stem cell markers CD133 and ALDH1, pluripotency maintaining factors Nanog, Sox2 and Oct4, oncogenic transcription factor c-Myc, signaling molecule Notch1, and drug resistant gene ABCG2. Moreover, SP cells consistently demonstrated significantly greater tumorigenicity than NSP cells in xenograft model of nude mice. CdODN–SOC efficiently suppressed all CSC properties and phenotypes, and minimized the tumorigenic capability of the SP cells and the resistance to chemotherapy. By comparison, the negative control failed to do so.ConclusionThe findings indicate that targeting the key genes conferring the stemness of CSCs can efficiently eliminate CSC-like phenotypes, and thus may be considered a new approach for cancer therapy. Specifically, the present study establishes the combination of Sox2/Oct4/c-Myc targeting as a potential anti-pancreatic cancer agent worthy of further studies in preclinical settings.

Accumulating studies demonstrate the critical role of circular RNAs (circRNAs) in the pathogenesis of various types of cancers. Previously, hsa_circ_0034642 has been found elevated in glioma tissues compared with the normal tissues, as proved by high-throughput microarray. We further investigated its expression level in 52 paired tissues and different glioma cell lines by quantitative reverse transcription-polymerase chain reaction. In addition, Fisher's exact test, Kaplan-Meier curves, and Cox analyses were performed to elucidate the clinical significance of hsa_circ_0034642. For the part of functional assays, gain/ loss-of-function assays were conducted to measure cell growth, apoptosis, and metastatic properties affected by hsa_circ_0034642. Furthermore, the mechanisms of hsa_circ_0034642 were investigated by dual-luciferase reporter assays. As the results demonstrated, hsa_circ_0034642 was boosted in glioma tissues and cells. Overexpression of hsa_circ_0034642 was associated with clinical severity and poor prognosis. What is more, elevated hsa_circ_0034642 strikingly facilitated cell proliferation, migratory and invasive capacities, and decreased apoptotic cells. Mechanistically, hsa_circ_0034642 sponges miR-1205. miR-1205 regulates BATF3 level through targeting its 3′-untranslated region. In summary, hsa_circ_0034642 might play a key role in this malignancy. K E Y W O R D Scircular RNA, glioma, hsa_circ_0034642, miR-1205

Desmogleins (DSGs), with the ability to link adjacent cells, have been shown to participate in the development of malignancy. DSG3 was up-regulated in various cancers, including lung, head and neck, and esophagus squamous cell carcinoma, which contributed to the tumor progression. The role of DSG3 in pancreatic ductal adenocarcinoma (PDAC) still remains elusive. Here, the expression of DSG3 was found to be enhanced in pancreatic cancer cell lines in vitro. Functional assays showed that shRNA-mediated knockdown of DSG3 decreased cell viability of pancreatic cancer cells and retarded the cell proliferation, migration and invasion. However, pcDNAmediated over-expression of DSG3 exhibited reversed effect on pancreatic cancer cell progression. In addition, the in vivo assay demonstrated that transfection of shDSG3 lentiviruses into pancreatic cancer cells repressed the tumorigenicity of PDAC after the cancer cells were transplanted into mice subcutaneously. Elevated DSG3 expression promoted the phosphorylation of Src (p-Src), focal adhesion kinase (p-FAK) and AKT (p-AKT) in vitro, while silence of DSG3 reduced the expression of p-Src, p-FAK and p-AKT both in vitro and in vivo. In conclusion, DSG3, as an oncogene, contributed to the tumorigenicity of PDAC through activating Src-FAK signaling.

The present study explored the correlation of ecotropic viral integration site 5 (EVI5) expression with clinicopathological features and prognosis in hepatocellular carcinoma (HCC). A total of 205 HCC patients were included retrospectively. Quantitative real-time polymerase chain reaction (RT-qPCR) and western blotting were performed to detect the profile of EVI5 expression in HCC cell lines and fresh tissues. Archived paraffin-embedded specimens were investigated for EVI5 expression by immunohistochemistry (IHC). Both the mRNA and protein levels of EVI5 were obviously upregulated in HCC cell lines and tumor tissues. EVI5 protein level was closely associated with the clinicopathological characteristics, including liver function (P=0.013), venous invasion (P=0.015) and TNM stage (P=0.014). Furthermore, univariate analysis showed that the patients with high EVI5 expression indicated shorter overall survival (OS, P<0.001) and recurrence-free survival (RFS, P=0.001) than those with low EVI5 expression. Importantly, high EVI5 expression also exerts predictive power for higher postoperative recurrence rate by stratified analysis. Multivariate Cox regression analysis demonstrated that OS was correlated with both tumor number (P=0.046) and EVI5 expression (P<0.001) and that RFS was correlated with serum AFP (P=0.023), tumor number (P=0.036) and EVI5 expression (P<0.001). Taken together, EVI5 is an useful independent prognostic marker of survival and recurrence in hepatocellular carcinoma.

The present study focused on the roles of members of the Hedgehog (Hh) signaling pathway in the maintenance of malignant biological characteristics, such as tumorigenesis, similar to that of pancreatic tumor cells. Cluster of differentiation (CD)44+CD24+/CD44−CD24− cells were isolated from three different pancreatic cancer cell lines by flow cytometry. Among the three pancreatic cancer cell lines, the SW1990 cell line exhibited the highest percentage of CD44+CD24+ cells, which accounted for 39.9% of the total. The expression of members of the Hh signaling pathway in CD44+CD24+/CD44−CD24− cells was detected using reverse transcription-polymerase chain reaction and western blot analysis. The results demonstrated that members of the Hh signaling pathway were differentially expressed in CD44+CD24+ cells compared with CD44−CD24−, normal pancreatic duct cells and unsorted SW1990 cells. In addition, lentiviral expression vectors expressing Smoothened (Smo) small interfering RNA (siRNA) were constructed. Following transfection with the lentiviral expression vectors, Smo expression was markedly reduced in CD44+CD24+ cells. The present study represents a preliminary investigation into the biological characteristics of CD44+CD24+ pancreatic cancer cells.