Pancreatic cancer foiled by a switch of tumour subtype

Oxysterol-Binding Protein 2 Promotes Pancreatic Ductal Adenocarcinoma Progression Through Epithelial-Mesenchymal Transition

Oxysterol-binding protein 2 (OSBP2) is crucial for promoting the growth and development of cancers; however, its effects on pancreatic ductal adenocarcinoma (PDAC) are still unclear. Here, we report that OSBP2 is an efficient tumor-associated protein to lead to extremely malignant characteristics in PDAC. We discovered that increased OSBP2 expression in primary tumors was associated with shorter survival in PDAC patients. Therefore, we used immunohistochemistry (IHC) to analyze the levels of OSBP2 expression in PDAC tissues and adjacent paracancerous tissues. We used wound healing and Transwell assays to evaluate the effects of OSBP2 on PDAC cell (ASPC-1 and BXPC-3) migration and invasion, respectively, and CCK-8 and Annexin V/PI double staining to evaluate the effects of OSBP2 on PDAC cell proliferation and apoptosis, respectively. Western blotting was used to analyze the effect of OSBP2 on the PDAC cell phenotype. We also explored the effect of OSBP2 on chemosensitivity to gemcitabine (GEM) and 5-fluorouracil (5-FU). We validated these findings in an in vivo mouse model. The data show that OSBP2 overexpression promoted PDAC cell migration, invasion, proliferation and chemotherapy resistance, and decreased apoptosis. OSBP2 overexpression downregulated E-cadherin expression and upregulated N-cadherin, vimentin, Snail, Slug, ZEB1, and β-catenin expression. Taken together, our findings indicated that OSBP2 was overexpressed in PDAC and that upregulation of OSBP2 may promote PDAC progression. Therefore, OSBP2 may have potential diagnostic and therapeutic value in PDAC.

Drivers of Gene Expression Dysregulation in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) remains a devastating disease with a poor prognosis. The functional consequences of common genetic aberrations and their roles in treatment strategies have been extensively reviewed. In addition to these genomic aberrations, consideration of non-genetic drivers of altered oncogene expression is essential to account for the diversity in PDAC phenotypes. In this review we seek to assess our current understanding of mechanisms of gene expression dysregulation. We focus on four drivers of gene expression dysregulation, including mutations, transcription factors, epigenetic regulators, and RNA stability/isoform regulation, in the context of PDAC pathogenesis. Recent studies provide much-needed insight into the role of gene expression dysregulation in dissecting tumor heterogeneity and stratifying patients for the development of personalized treatment strategies.

HOXB5 promotes malignant progression in pancreatic cancer via the miR-6732 pathway

Background: Homeobox B5 (HOXB5) is associated with the poor prognosis of various cancer types. However, the specific mechanism by which HOXB5 promotes the malignant progression of pancreatic cancer (PC) remains to be determined.Methods: The Cancer Genome Atlas database indicated HOXB5 expression level correlated to PC prognosis. The biological functions of HOXB5 was confirmed by colony formation, migration, and invasion assays. The effects of HOXB5 on the expression of cancer stem cell and epithelial-mesenchymal transition markers were evaluated. The downstream target of HOXB5 was miR-6723, which was detected by transcriptional assay. A xenograft tumor model was established in nude mice for the assessment of the role of HOXB5 in tumor growth and metastasis.Results: PC tissues had higher HOXB5 expression levels than noncancerous tissues, and high HOXB5 expression was significantly associated with poor PC prognosis. HOXB5 knockdown suppressed clone formation and the proliferation, invasion, and migration of PC cells in vitro. Conversely, these activities were enhanced by HOXB5 overexpression. The HOXB5 that bound two synergy motifs regulated miR-6723 expression and contributed to PC malignant progression. The role of HOXB5 in promoting tumor growth and metastasis was verified in vivo. Further investigation revealed that Twist1 and Zeb1 expression levels were increased by HOXB5.Conclusions: HOXB5 overexpression was significantly correlated with poor PC prognosis. HOXB5 accelerated the malignant progression of PC by up-regulating miR-6723, which afforded PC cells stem-like properties and facilitated the epithelial-mesenchymal transition of PC cells.

Ruscogenin induces ferroptosis in pancreatic cancer cells

Pancreatic cancer is characterized by aggressive and highly metastatic phenotypes. This disease exhibits a poor patient prognosis and is considered a challenge due to the limited treatment options encountered in clinical practice. Previous studies have shown that ruscogenin, a saponin found in the root of Ophiopogon japonicus, exerts a wide range of biological functions including anticancer activity. In the present study, the effects of ruscogenin were investigated on pancreatic cancer cells and the potential molecular mechanism of this compound was explored. Cell viability was assessed using the 3-(4,5-di-2-yl)-2,5-ditetrazolium bromide (MTT) assay. Cell death was measured by trypan blue staining and by flow cytometry. The number of iron oxide nanoparticles was measured using Prussian blue staining. Reactive oxygen species (ROS) production was assessed using flow cytometry with dihydroethidium staining. Protein expression of the associated genes was assayed by western blotting. Furthermore, in vivo experiments were conducted to confirm the antitumor effects and assay the potential toxicity of ruscogenin in a nude mouse xenograft model. The results indicated that ruscogenin significantly repressed cell viability and induced cell death of pancreatic cancer cells in vitro in a dose- and time-dependent manner. Furthermore, ruscogenin increased the concentration of intracellular ferrous irons and the production of ROS. This effect was inhibited by deferoxamine (DFO). Ruscogenin induced ferroptosis by regulating the levels of transferrin and ferroportin. These two proteins were involved in ruscogenin-induced pancreatic cancer cell death. Finally, in vivo experiments demonstrated the antitumor effect of ruscogenin on pancreatic cancer xenografts in the absence of apparent toxicity. Taken collectively, the data demonstrated that ruscogenin exhibited anticancer effects in pancreatic cancer cells by inducing ferroptosis. The findings suggested that this compound may be further developed as a promising anticancer candidate for the treatment of pancreatic cancer.

HSP27 promotes epithelial-mesenchymal transition through activation of the β-catenin/MMP3 pathway in pancreatic ductal adenocarcinoma cells

Background

The precise role of heat shock protein 27 (HSP27), as a type of small molecular protein in HSPs, in pancreatic ductal adenocarcinoma (PDAC) remains to be elucidated. The aim of the present study was to investigate the expression and function of HSP27 in PDAC cells.

Methods

We first detected the expression of HSP27 in PDAC tissues. Combining with the clinical pathology characteristics of PDAC patients, the relationship between them was analyzed. Then, we knocked down HSP27 using short interfering RNA (siRNA) and observed its biological functions using scratch assay and matrigel invasion and migration assays in ASPC-1 and PANC-1 cells. In mechanism, we verified the β-catenin/MMP-3 pathway associated proteins in ASPC-1 and PANC-1 cells.

Results

We found that HSP27 was highly expression in PDAC tissues, and was positively correlated with tumor differentiation, TNM staging and poor prognosis of PDAC patients. In vitro, we down-regulated the expression of HSP27 in ASPC-1 and PANC-1 cells and found that the invasion and migration ability of PDAC cells were significantly depressed, meanwhile, the activation of the β-catenin/MMP-3 pathway was inhibited.

Conclusions

HSP27 may be used as a tumor biomarker for diagnosis of PDAC, and HSP27 can promote the invasion and migration of PDAC by activating the β-catenin/MMP3 Pathway. Therefore, inhibition of HSP27 has therapeutic potential for the treatment of PDAC.