Background: Accumulation evidence indicates the vital role of long non-coding RNAs (lncRNAs) in tumorigenesis and the progression of malignant tumors, including pancreatic cancer (PC). However, the role and the molecular mechanism of long non-coding RNA 00976 is unclear in pancreatic cancer. Methods: In situ hybridization (ISH) and qRT-PCR was performed to investigate the association between linc00976 expression and the clinicopathological characteristics and prognosis of patients with PC. Subsequently, linc00976 over-expression vector and shRNAs were transfected into PC cells to up-regulate or down-regulate linc00976 expression. Loss- and gain-of function assays were performed to investigate the role of linc00976 in proliferation and metastasis in vitro and vivo. ITRAQ, bioinformatic analysis and rescue assay were used to illustrate the ceRNA mechanism network of linc00976/miR-137/OTUD7B and its downstream EGFR/MAPK signaling pathway. Results: linc00976 expression was overexpressed in PC tissues and cell lines and was positively associated with poorer survival in patients with PC. Function studies revealed that linc00976 knockdown significantly suppressed cell proliferation, migration and invasion in vivo and in vitro, whereas its overexpression reversed these effects. Based on Itraq results and online database prediction, Ovarian tumor proteases OTUD7B was found as a downstream gene of linc00976, which deubiquitinated EGFR mediates MAPK signaling activation. Furthermore, Bioinformatics analysis and luciferase assays and rescue experiments revealed that linc00976/miR137/OTUD7B established the ceRNA network modulating PC cell proliferation and tumor growth. Conclusion: The present study demonstrates that linc00976 enhances the proliferation and invasion ability of PC cells by upregulating OTUD7B expression, which was a target of miR-137. Ultimately, OTUD7B mediates EGFR and MAPK signaling pathway, suggesting that linc00976/miR-137/OTUD7B/EGFR axis may act as a potential biomarker and therapeutic target for PC.

Pancreatic stellate cells (PSCs) are important components of the tumor microenvironment in pancreatic cancer (PC) and contribute to its development and metastasis through mechanisms that remain incompletely characterized. Tumor hypoxia affects the function and behavior of PC and stromal cells, and can alter exosomal content to modify cell-cell communication. The present study explored the effects of exosomal miRNAs produced by hypoxia-preconditioned PSCs on the growth and metastatic potential of PC cells. Subcutaneous xenografts and liver metastasis mouse models revealed increased tumorigenic potential upon co-implantation of PC cells and PSCs as compared to PC cells alone. Screening miRNA profiles of mouse plasma exosomes and cultured PSCs, followed by miRNA overexpression and inhibition assays, enabled us to identify miR-4465 and miR-616-3p as prominent hypoxia-induced, PSC-derived, exosomal miRNAs promoting PC cell proliferation, migration, and invasion. Proteomics analysis of PC cells incubated with exosomes derived from hypoxic PSCs showed significant downregulation of PTEN. Dual-luciferase reporter assays and western blotting showed that both miR-4465 and miR-616-3p target PTEN and activate AKT signaling in PC cells. We conclude that hypoxia upregulates miR-4465 and miR-616-3p expression in PSC-derived exosomes. Following exosome uptake, these miRNAs promote PC progression and metastasis by suppressing the PTEN/AKT pathway.

Long noncoding RNAs (lncRNAs) are a novel class of noncoding RNAs that have emerged as critical regulators and biomarkers in various cancers. Nevertheless, the expression profile and mechanistic function of lncRNAs in cholangiocarcinoma (CCA) remain unclear. Herein, we examined the expression levels of linc00976 in clinical specimens and cell lines using reverse transcription-quantitative PCR. In total, 50 patients with CCA were enrolled to analyze the correlation between linc00976 expression and clinical characteristics of CCA. Loss- and gain-of-function experiments were performed to investigate the biological effects of linc00976 on proliferation, ferroptosis, migration, and invasion of CCA cells in vitro and in vivo. In situ hybridization, RNA immunoprecipitation, bioinformatic databases, RNA pull-down assay, a dual-luciferase reporter assay, mRNA sequencing, chromatin immunoprecipitation–PCR, and rescue experiments were performed to elucidate the underlying mechanisms of linc00976-induced competitive endogenous RNA regulatory networks. We characterized a novel and abundant lncRNA, linc00976, that functions as a pro-oncogenic regulator of CCA progression. Compared with normal controls, linc00976 was dramatically upregulated in CCA tissue samples and cell lines. Patients with CCA exhibiting high linc00976 expression had a highly advanced clinical stage, substantial lymph node metastasis, and poor overall survival. Knockdown of linc00976 significantly repressed proliferation and metastasis and promoted ferroptosis of CCA cells both in vitro and in vivo, whereas linc00976 overexpression exerted the opposite effect. Mechanistically, linc00976 competitively interacted with miR-3202 to upregulate GPX4 expression, thus contributing to the malignant biological behavior of CCA cells. Moreover, we demonstrated that JUND specifically interacts with the linc00976 promoter and activates linc00976 transcription. Accordingly, JUND promotes linc00976 transcription, and linc00976 plays a crucial role in accelerating CCA tumorigenesis and metastasis and inhibiting ferroptosis by modulating the miR-3202/GPX4 axis. These findings suggest that targeting linc00976 may afford a promising therapeutic strategy for patients with CCA.

The pancreatic stellate cells (PSCs) play an important role in the development of pancreatic cancer (PC) through mechanisms that remain unclear. Exosomes secreted from PSCs act as mediators for communication in PC. This study aimed to explore the role of PSC‐derived exosomal small RNAs derived from tRNAs (tDRs) in PC cells. Exosomes from PSCs were extracted and used to detect their effects on PC cell proliferation, migration and invasion. Exosomal tDRs profiling was performed to identify PSC‐derived exosomal tDRs. ISH and qRT‐PCR were used to examine the tRF‐19‐PNR8YPJZ levels and clinical value in clinical samples. The biological function of exosomal tRF‐19‐PNR8YPJZ was determined using the CCK‐8, clone formation, wound healing and transwell assays, subcutaneous tumour formation and lung metastatic models. The relationship between the selected exosomal tRF‐19‐PNR8YPJZ and AXIN2 was determined by RNA sequencing, luciferase reporter assay. PSC‐derived exosomes promoted the proliferation, migration, and invasion of PC cells. Novel and abundant tDRs are found to be differentially expressed in PANC‐1 cells after treatment with PSC‐derived exosomes, such as tRF‐19‐PNR8YPJZ. PC tissue samples showed markedly higher levels of tRF‐19‐PNR8YPJZ than normal controls. Patients with PC exhibiting high tRF‐19‐PNR8YPJZ expression had a highly lymph node invasion, metastasis, perineural invasion, advanced clinical stage and poor overall survival. Exosomal tRF‐19‐PNR8YPJZ from PSCs targeted AXIN2 in PC cells and decreased its expression, thus activating the Wnt pathway and promoting proliferation and metastasis. Exosomal tRF‐19‐PNR8YPJZ from PSCs promoted proliferation and metastasis in PC cells via AXIN2.

The oncogenic properties of members belonging to the forkhead box (FOX) family have been extensively documented in different types of cancers. In this study, our objective was to investigate the impact of FOXP3 on glioblastoma multiforme (GBM) cells. By conducting a screen using a small hairpin RNA (shRNA) library, we discovered a significant association between FOXP3 and ferroptosis in GBM cells. Furthermore, we observed elevated levels of FOXP3 in both GBM tissues and cell lines, which correlated with a poorer prognosis. FOXP3 was found to promote the proliferation of GBM cells by inhibiting cell ferroptosis in vitro and in vivo. Mechanistically, FOXP3 not only directly upregulated the transcription of GPX4, but also attenuated the degradation of GPX4 mRNA through the linc00857/miR-1290 axis, thereby suppressing ferroptosis and promoting proliferation. Additionally, the FOXP3 inhibitor epirubicin exhibited the ability to impede proliferation and induce ferroptosis in GBM cells both in vitro and in vivo. In summary, our study provided evidences that FOXP3 facilitates the progression of glioblastoma by inhibiting ferroptosis via the linc00857/miR-1290/GPX4 axis, highlighting FOXP3 as a potential therapeutic target for GBM.