Ribosome 18S m6A methyltransferase METTL5 promotes pancreatic cancer progression by modulating c‑Myc translation

AbstractAn accumulation of evidence indicates that long noncoding RNAs are involved in the tumorigenesis and progression of pancreatic cancer (PC). In this study, we investigated the functions and molecular mechanism of action of LINC00941 in PC. Quantitative PCR was used to examine the expression of LINC00941 and miR-335-5p in PC tissues and cell lines, and to investigate the correlation between LINC00941 expression and clinicopathological features. Plasmid vectors or lentiviruses were used to manipulate the expression of LINC00941, miR-335-5p, and ROCK1 in PC cell lines. Gain or loss-of-function assays and mechanistic assays were employed to verify the roles of LINC00941, miR-335-5p, and ROCK1 in PC cell growth and metastasis, both in vivo and in vitro. LINC00941 and ROCK1 were found to be highly expressed in PC, while miR-335-5p exhibited low expression. High LINC00941 expression was strongly associated with larger tumor size, lymph node metastasis, and poor prognosis. Functional experiments revealed that LINC00941 silencing significantly suppressed PC cell growth, metastasis and epithelial–mesenchymal transition. LINC00941 functioned as a molecular sponge for miR-335-5p, and a competitive endogenous RNA (ceRNA) for ROCK1, promoting ROCK1 upregulation, and LIMK1/Cofilin-1 pathway activation. Our observations lead us to conclude that LINC00941 functions as an oncogene in PC progression, behaving as a ceRNA for miR-335-5p binding. LINC00941 may therefore have potential utility as a diagnostic and treatment target in this disease.

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MIB1 upregulates IQGAP1 and promotes pancreatic cancer progression by inducing ST7 degradation

Molecular Oncology ◽

10.1002/1878-0261.12955 ◽

2021 ◽

Author(s):

Bin Zhang ◽

Xiang Cheng ◽

Sudong Zhan ◽

Xin Jin ◽

Tao Liu

Keyword(s):

Pancreatic Cancer ◽

Cancer Progression

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Hypoxia promotes the metastasis of pancreatic cancer through regulating NOX4/KDM5A-mediated histone methylation modification changes in a HIF1A-independent manner

Clinical Epigenetics ◽

10.1186/s13148-021-01016-6 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Hongzhen Li ◽

Chunyan Peng ◽

Chenhui Zhu ◽

Shuang Nie ◽

Xuetian Qian ◽

...

Keyword(s):

Pancreatic Cancer ◽

Nadph Oxidase ◽

Western Blot ◽

Cancer Progression ◽

Histone Methylation ◽

Invasion And Metastasis ◽

Independent Manner ◽

Nadph Oxidase 4

Abstract Background Hypoxia is a characteristic of the tumor microenvironments within pancreatic cancer (PC), which has been linked to its malignancy. Recently, hypoxia has been reported to regulate the activity of important carcinogenic pathways by changing the status of histone modification. NOX4, a member of NADPH oxidase (NOX), has been found to be activated by hypoxia and promote cancer progression in several cancers. But whether it is involved in the epigenetic changes of tumor cells induced by hypoxia is still unclear, and its biological roles in PC also need to be explored. Methods A hypoxic-related gene signature and its associated pathways in PC were identified by analyzing the pancreatic cancer gene expression data from GEO and TCGA database. Candidate downstream gene (NOX4), responding to hypoxia, was validated by RT-PCR and western blot. Then, we evaluated the relationship between NOX4 expression and clinicopathologic parameters in 56 PC patients from our center. In vitro and in vivo assays were preformed to explore the phenotype of NOX4 in PC. Immunofluorescence, western blot and chromatin immunoprecipitation assays were further applied to search for a detailed mechanism. Results We quantified hypoxia and developed a hypoxia signature, which was associated with worse prognosis and elevated malignant potential in PC. Furthermore, we found that NADPH oxidase 4 (NOX4), which was induced by hypoxia and upregulated in PC in a HIF1A-independent manner, caused inactivation of lysine demethylase 5A (KDM5A), increased the methylation modification of histone H3 and regulated the transcription of EMT-associated gene_ snail family transcriptional repressor 1 (SNAIL1). This served to promote the invasion and metastasis of PC. NOX4 deficiency repressed hypoxia-induced EMT, reduced expression of H3K4ME3 and impaired the invasion and metastasis of PC cells; however, knockdown of KDM5A reversed the poor expression of H3KEME3 induced by NOX4 deficiency, thereby promoting EMT. Conclusions This study highlights the prognostic role of hypoxia-related genes in PC and strong correlation with EMT pathway. Our results also creatively discovered that NOX4 was an essential mediator for hypoxia-induced histone methylation modification and EMT in PC cells.

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HGF/c-Met Inhibition as Adjuvant Therapy Improves Outcomes in an Orthotopic Mouse Model of Pancreatic Cancer

Cancers ◽

10.3390/cancers13112763 ◽

2021 ◽

Vol 13 (11) ◽

pp. 2763

Author(s):

Tony C. Y. Pang ◽

Zhihong Xu ◽

Alpha Raj Mekapogu ◽

Srinivasa Pothula ◽

Therese Becker ◽

...

Keyword(s):

Pancreatic Cancer ◽

Cancer Progression ◽

Stellate Cell ◽

Smooth Muscle Actin ◽

Primary Tumour ◽

Human Pancreatic Cancer ◽

Pancreatic Stellate Cell ◽

Orthotopic Mouse Model ◽

Pancreatic Cancer Cells ◽

Angiogenic Effect

Background: Inhibition of hepatocyte growth factor (HGF)/c-MET pathway, a major mediator of pancreatic stellate cell (PSC)−PC cell interactions, retards local and distant cancer progression. This study examines the use of this treatment in preventing PC progression after resection. We further investigate the postulated existence of circulating PSCs (cPSCs) as a mediator of metastatic PC. Methods: Two orthotopic PC mouse models, produced by implantation of a mixture of luciferase-tagged human pancreatic cancer cells (AsPC-1), and human PSCs were used. Model 1 mice underwent distal pancreatectomy 3-weeks post-implantation (n = 62). One-week post-resection, mice were randomised to four treatments of 8 weeks: (i) IgG, (ii) gemcitabine (G), (iii) HGF/c-MET inhibition (HiCi) and (iv) HiCi + G. Tumour burden was assessed longitudinally by bioluminescence. Circulating tumour cells and cPSCs were enriched by filtration. Tumours of Model 2 mice progressed for 8 weeks prior to the collection of primary tumour, metastases and blood for single-cell RNA-sequencing (scRNA-seq). Results: HiCi treatments: (1) reduced both the risk and rate of disease progression after resection; (2) demonstrated an anti-angiogenic effect on immunohistochemistry; (3) reduced cPSC counts. cPSCs were identified using immunocytochemistry (α-smooth muscle actin+, pan-cytokeratin−, CD45−), and by specific PSC markers. scRNA-seq confirmed the existence of cPSCs and identified potential genes associated with development into cPSCs. Conclusions: This study is the first to demonstrate the efficacy of adjuvant HGF/c-Met inhibition for PC and provides the first confirmation of the existence of circulating PSCs.

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NR5A2 transcriptional activation by BRD4 promotes pancreatic cancer progression by upregulating GDF15

Cell Death Discovery ◽

10.1038/s41420-021-00462-8 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Feng Guo ◽

Yingke Zhou ◽

Hui Guo ◽

Dianyun Ren ◽

Xin Jin ◽

...

Keyword(s):

Pancreatic Cancer ◽

Cancer Cells ◽

Cancer Progression ◽

Transcriptional Activation ◽

Ductal Adenocarcinoma ◽

Pancreatic Cancer Cells ◽

Gene Sets ◽

And Migration

AbstractNR5A2 is a transcription factor regulating the expression of various oncogenes. However, the role of NR5A2 and the specific regulatory mechanism of NR5A2 in pancreatic ductal adenocarcinoma (PDAC) are not thoroughly studied. In our study, Western blotting, real-time PCR, and immunohistochemistry were conducted to assess the expression levels of different molecules. Wound-healing, MTS, colony formation, and transwell assays were employed to evaluate the malignant potential of pancreatic cancer cells. We demonstrated that NR5A2 acted as a negative prognostic biomarker in PDAC. NR5A2 silencing inhibited the proliferation and migration abilities of pancreatic cancer cells in vitro and in vivo. While NR5A2 overexpression markedly promoted both events in vitro. We further identified that NR5A2 was transcriptionally upregulated by BRD4 in pancreatic cancer cells and this was confirmed by Chromatin immunoprecipitation (ChIP) and ChIP-qPCR. Besides, transcriptome RNA sequencing (RNA-Seq) was performed to explore the cancer-promoting effects of NR5A2, we found that GDF15 is a component of multiple down-regulated tumor-promoting gene sets after NR5A2 was silenced. Next, we showed that NR5A2 enhanced the malignancy of pancreatic cancer cells by inducing the transcription of GDF15. Collectively, our findings suggest that NR5A2 expression is induced by BRD4. In turn, NR5A2 activates the transcription of GDF15, promoting pancreatic cancer progression. Therefore, NR5A2 and GDF15 could be promising therapeutic targets in pancreatic cancer.

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