MicroRNA-216a enhances the radiosensitivity of pancreatic cancer cells by inhibiting beclin-1-mediated autophagy

Molecular mechanisms in regulation of autophagy and apoptosis in view of epigenetic regulation of genes and involvement of liquid-liquid phase separation

Cellular physiology is critically regulated by multiple signaling nexuses, among which cell death mechanisms play crucial roles in controlling the homeostatic landscape at the tissue level within an organism. Apoptosis, also known as programmed cell death, can be induced by external and internal stimuli directing the cells to commit suicide in unfavourable conditions. In contrast, stress conditions like nutrient deprivation, infection and hypoxia trigger autophagy, which is lysosome-mediated processing of damaged cellular organelle for recycling of the degraded products, including amino acids. Apparently, apoptosis and autophagy both are catabolic and tumor-suppressive pathways; apoptosis is essential during development and cancer cell death, while autophagy promotes cell survival under stress. Moreover, autophagy plays dual role during cancer development and progression by facilitating the survival of cancer cells under stressed conditions and inducing death in extreme adversity. Despite having two different molecular mechanisms, both apoptosis and autophagy are interconnected by several crosslinking intermediates. Epigenetic modifications, such as DNA methylation, post-translational modification of histone tails, and miRNA play a pivotal role in regulating genes involved in both autophagy and apoptosis. Both autophagic and apoptotic genes can undergo various epigenetic modifications and promote or inhibit these processes under normal and cancerous conditions. Epigenetic modifiers are uniquely important in controlling the signaling pathways regulating autophagy and apoptosis. Therefore, these epigenetic modifiers of both autophagic and apoptotic genes can act as novel therapeutic targets against cancers. Additionally, liquid-liquid phase separation (LLPS) also modulates the aggregation of misfolded proteins and provokes autophagy in the cytosolic environment. This review deals with the molecular mechanisms of both autophagy and apoptosis including crosstalk between them; emphasizing epigenetic regulation, involvement of LLPS therein, and possible therapeutic approaches against cancers.

Targeting autophagy and beyond: Deconvoluting the complexity of Beclin-1 from biological function to cancer therapy

Beclin-1 is the firstly-identified mammalian protein of the autophagy machinery, which functions as a molecular scaffold for the assembly of PI3KC3 (class III phosphatidylinositol 3 kinase) complex, thus controlling autophagy induction and other cellular trafficking events. Notably, there is mounting evidence establishing the implications of Beclin-1 in diverse tumorigenesis processes, including tumor suppression and progression as well as resistance to cancer therapeutics and CSC (cancer stem-like cell) maintenance. More importantly, Beclin-1 has been confirmed as a potential target for the treatment of multiple cancers. In this review, we provide a comprehensive survey of the structure, functions, and regulations of Beclin-1, and we discuss recent advances in understanding the controversial roles of Beclin-1 in oncology. Moreover, we focus on summarizing the targeted Beclin-1-regulating strategies in cancer therapy, providing novel insights into a promising strategy for regulating Beclin-1 to improve cancer therapeutics in the future.

Curcumin modulates cell type-specific miRNA networks to induce cytotoxicity in ovarian cancer cells

AIM

To understand the epigenetic role of curcumin, a natural polyphenolic compound extracted from the spice Curcuma longa in inducing cytotoxicity in two molecularly distinct ovarian cancer cell lines: PA1 and A2780.

MATERIALS AND METHODS

An integrated mRNA-miRNA sequence analysis was performed to determine the curcumin-induced mRNA-miRNA regulatory networks in the induction of cytotoxicity. The miRNA-mRNA pathways, the miRNAs and their targets implicated in apoptosis, autophagy, DNA damage, and stemness markers were validated. Gene/miRNA expressions were validated using qPCR and protein expressions by western blotting. Curcumin-induced oncogenic /tumor-suppressor miRNAs were profiled utilising the oncomiRdb database. Similarly, the expressions of oncogenes/tumor suppressor genes were profiled and correlated with the TCGA ovarian cancer dataset. A dual luciferase assay was performed to investigate the interaction of miR-199a-5p to its direct target, DDR1.

KEY FINDINGS

The expression of several miRNAs demonstrated an inverse correlation with their respective direct targets. In curcumin-treated PA1 cells, miR-335-5p target ATG5 (autophagic), and OCT4 (pluripotent gene) were downregulated, miR-32a target PTEN (tumor suppressor) was upregulated, miR-1285 target P53 (tumor suppressor) was upregulated, and both miR-182-5p and miR-503-3p target BCL2, were down-regulated. Contrastingly, in curcumin-treated A2780 cells, miR-181a-3p target ATG5, miR-30a-5p, and miR-216a target BECN1 (autophagic) were upregulated, and miR-129a-5p target BCL2 were downregulated. The reversal of the oncomiR/TSmiR profile revealed suppression of oncogenic processes by curcumin. Curcumin treatment induced a moderate cisplatin-sensitisation effect and impaired epithelial-to-mesenchymal transition (EMT) characteristics. Curcumin also regulated the miR-199a-5p/DDR1 axis with a decrease in collagen deposition.

SIGNIFICANCE

The activity of curcumin is cell-type specific. Distinct miRNA regulatory networks were activated to induce multiple modes of cellular cytotoxicity in these ovarian cancer cells. This study further highlights the molecular mechanism of curcumin action in ovarian cancers establishing its candidacy as a promising drug candidate.

Microbiome and MicroRNA or Long Non-Coding RNA-Two Modern Approaches to Understanding Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of humans' most common and fatal neoplasms. Nowadays, a number of PDAC studies are being conducted in two different fields: non-coding RNA (especially microRNA and long non-coding RNA) and microbiota. It has been recently discovered that not only does miRNA affect particular bacteria in the gut microbiome that can promote carcinogenesis in the pancreas, but the microbiome also has a visible impact on the miRNA. This suggests that it is possible to use the combined impact of the microbiome and noncoding RNA to suppress the development of PDAC. Nevertheless, insufficient research has focused on bounding both approaches to the diagnosis, treatment, and prevention of pancreatic ductal adenocarcinoma. In this article, we summarize the recent literature on the molecular basis of carcinogenesis in the pancreas, the two-sided impact of particular types of non-coding RNA and the pancreatic cancer microbiome, and possible medical implications of the discovered phenomenon.

A bioinformatics analysis, pre-clinical and clinical conception of autophagy in pancreatic cancer: Complexity and simplicity in crosstalk

Pancreatic cancer (PC) is a serious gastrointestinal tract disease for which the 5-year survival rate is less than 10%, even in developed countries such as the USA. The genomic profile alterations and dysregulated biological mechanisms commonly occur in PC. Macroautophagy/autophagy is a cell death process that is maintained at a basal level in physiological conditions, whereas its level often changes during tumorigenesis. The function of autophagy in human cancers is dual and can be oncogenic and onco-suppressor. Autophagy is a potent controller of tumorigenesis in PC. The supportive autophagy in PC escalates the growth rate of PC cells and its suppression can mediate cell death. Autophagy also determines the metastasis of PC cells, and it can control the EMT in affecting migration. Moreover, starvation and hypoxia can stimulate glycolysis, and glycolysis induction can be mediated by autophagy in enhancing tumorigenesis in PC. Furthermore, protective autophagy stimulates drug resistance and gemcitabine resistance in PC cells, and its inhibition can enhance radiosensitivity. Autophagy can degrade MHC-I to mediate immune evasion and also regulates polarization of macrophages in the tumor microenvironment. Modulation of autophagy activity is provided by silibinin, ursolic acid, chrysin and huaier in the treatment of PC. Non-coding RNAs are also controllers of autophagy in PC and its inhibition can improve therapy response in patients. Moreover, mitophagy shows dysregulation in PC, which can enhance the proliferation of PC cells. Therefore, a bioinformatics analysis demonstrates the dysregulation of autophagy-related proteins and genes in PC as biomarkers.

Non-coding RNAs in radiotherapy resistance: Roles and therapeutic implications in gastrointestinal cancer

Radiotherapy has become an indispensable and conventional means for patients with advanced solid tumors including gastrointestinal cancer. However, innate or acquired radiotherapy resistance remains a significant challenge and greatly limits the therapeutic effect, which results in cancer relapse and poor prognosis. Therefore, it is an urgent need to identify novel biomarkers and therapeutic targets for clarify the biological characteristics and mechanism of radiotherapy resistance. Recently, lots of studies have revealed that non-coding RNAs (ncRNAs) are the potential indicators and regulators of radiotherapy resistance via the mediation of various targets/pathways in different cancers. These findings may serve as a potential therapeutic strategy to overcome radiotherapy resistance. In this review, we will shed light on the recent findings regarding the functions and regulatory mechanisms of ncRNAs following radiotherapy, and comprehensively discuss their potential as biomarkers and therapeutic targets in radiotherapy resistance of gastrointestinal cancer.

Molecular mechanisms of microRNA-216a during tumor progression

MicroRNAs (miRNAs) as the members of non-coding RNAs family are involved in post-transcriptional regulation by translational inhibiting or mRNA degradation. They have a critical role in regulation of cell proliferation and migration. MiRNAs aberrations have been reported in various cancers. Considering the importance of these factors in regulation of cellular processes and their high stability in body fluids, these factors can be suggested as suitable non-invasive markers for the cancer diagnosis. MiR-216a deregulation has been frequently reported in different cancers. Therefore, in the present review we discussed the molecular mechanisms of the miR-216a during tumor progression. It has been reported that miR-216a mainly functioned as a tumor suppressor through the regulation of signaling pathways and transcription factors. This review paves the way to suggest the miR-216a as a probable therapeutic and diagnostic target in cancer patients.

Epigenetic regulation of autophagy by non-coding RNAs in gastrointestinal tumors: Biological functions and therapeutic perspectives

Cancer is the manifestation of changes and mutations in genetic and epigenetic levels. Non-coding RNAs (ncRNAs) are commonly dysregulated in disease pathogenesis, and their role in cancer has been well-documented. The ncRNAs regulate various molecular pathways and mechanisms in cancer that can lead to induction/inhibition of carcinogenesis. Autophagy is a molecular "self-digestion" mechanism its function can be pro-survival or pro-death in tumor cells. The aim of the present review is to evaluate the role of ncRNAs in regulating autophagy in gastrointestinal tumors. The role of the ncRNA/autophagy axis in affecting the progression of gastric, liver, colorectal, pancreatic, esophageal, and gallbladder cancers is investigated. Both ncRNAs and autophagy mechanisms can function as oncogenic or onco-suppressor and this interaction can determine the growth, invasion, and therapy response of gastrointestinal tumors. ncRNA/autophagy axis can reduce/increase the proliferation of gastrointestinal tumors via the glycolysis mechanism. Furthermore, related molecular pathways of metastasis, such as EMT and MMPs, are affected by the ncRNA/autophagy axis. The response of gastrointestinal tumors to chemotherapy and radiotherapy can be suppressed by pro-survival autophagy, and ncRNAs are essential regulators of this mechanism. miRNAs can regulate related genes and proteins of autophagy, such as ATGs and Beclin-1. Furthermore, lncRNAs and circRNAs down-regulate miRNA expression via sponging to modulate the autophagy mechanism. Moreover, anti-cancer agents can affect the expression level of ncRNAs regulating autophagy in gastrointestinal tumors. Therefore, translating these findings into clinics can improve the prognosis of patients.

Autophagy-Related ncRNAs in Pancreatic Cancer

Pancreatic cancer (PC) is a malignancy accounting for only 3% of total cancers, but with a low 5-year relative survival rate. Approximately 80% of PC patients are diagnosed at a late stage when the disease has already spread from the primary site. Despite advances in PC treatment, there is an urgently needed for the identification of novel therapeutic strategies for PC, particularly for patients who cannot undergo classical surgery. Autophagy is an evolutionarily conserved process used by cells to adapt to metabolic stress via the degrading or recycling of damaged or unnecessary organelles and cellular components. This process is elevated in PC and, thus, it contributes to the onset, progression, and cancer cell resistance to chemotherapy in pancreatic tumors. Autophagy inhibition has been shown to lead to cancer regression and to increase the sensitivity of pancreatic cells to radiation and chemotherapy. Emerging studies have focused on the roles of non-coding RNAs (ncRNAs), such as miRNAs, long non-coding RNAs, and circular RNAs, in PC development and progression. Furthermore, ncRNAs have been reported as crucial regulators of many biological processes, including autophagy, suggesting that ncRNA-based autophagy targeting methods could be promising novel molecular approaches for specifically reducing autophagic flux, thus improving the management of PC patients. In this review, we briefly summarize the existing studies regarding the role and the regulatory mechanisms of autophagy-related ncRNAs in the context of this cancer.

The Roles of MicroRNA in Pancreatic Cancer Progression

Pancreatic Ductal Adenocarcinoma (PDAC) has a poor patient survival rate in comparison with other cancer types, even after targeted therapy, chemotherapy, and immunotherapy. Therefore, a great deal needs to be done to gain a better understanding of the biology and identification of prognostic and predictive markers for the development of superior therapies. The microRNAs (miRNAs) belong to small non-coding RNAs that regulate post-transcriptional gene expression. Several shreds of evidence indicate that miRNAs play an important role in the pathogenesis of pancreatic cancer. Here we review the recent developments in miRNAs and their target role in the development, metastasis, migration, and invasion.

The Role of Non-Coding RNAs in Autophagy During Carcinogenesis

Macroautophagy (autophagy herein) is a cellular stress response and a survival pathway involved in self-renewal and quality control processes to maintain cellular homeostasis. The alteration of autophagy has been implicated in numerous diseases such as cancer where it plays a dual role. Autophagy serves as a tumor suppressor in the early phases of cancer formation with the restoration of homeostasis and eliminating cellular altered constituents, yet in later phases, autophagy may support and/or facilitate tumor growth, metastasis and may contribute to treatment resistance. Key components of autophagy interact with either pro- and anti-apoptotic factors regulating the proximity of tumor cells to apoptotic cliff promoting cell survival. Autophagy is regulated by key cell signaling pathways such as Akt (protein kinase B, PKB), mammalian target of rapamycin (mTOR) and AMP-activated protein kinase (AMPK) involved in cell survival and metabolism. The expression of critical members of upstream cell signaling, as well as those directly involved in the autophagic and apoptotic machineries are regulated by microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). Consequently, non-coding RNAs play a relevant role in carcinogenesis and treatment response in cancer. The review is an update of the current knowledge in the regulation by miRNA and lncRNA of the autophagic components and their functional impact to provide an integrated and comprehensive regulatory network of autophagy in cancer.

Radiosensitizing Pancreatic Cancer via Effective Autophagy Inhibition

Despite aggressive treatments, pancreatic ductal adenocarcinoma (PDAC) remains an intractable disease, largely because it is refractory to therapeutic interventions. To overcome its nutrient-poor microenvironment, PDAC heavily relies on autophagy for metabolic needs to promote tumor growth and survival. Here, we explore autophagy inhibition as a method to enhance the effects of radiotherapy on PDAC tumors. Hydroxychloroquine is an autophagy inhibitor at the focus of many PDAC clinical trials, including in combination with radiotherapy. However, its acid-labile properties likely reduce its intratumoral efficacy. Here, we demonstrate that EAD1, a synthesized analogue of HCQ, is a more effective therapeutic for sensitizing PDAC tumors of various KRAS mutations to radiotherapy. Specifically, in vitro models show that EAD1 is an effective inhibitor of autophagic flux in PDAC cells, accompanied by a potent inhibition of proliferation. When combined with radiotherapy, EAD1 is consistently superior to HCQ not only as a single agent, but also in radiosensitizing PDAC cells, and perhaps most importantly, in decreasing the self-renewal capacity of PDAC cancer stem cells (PCSC). The more pronounced sensitizing effects of autophagy inhibitors on pancreatic stem over differentiated cells points to a new understanding that PCSCs may be more dependent on autophagy to counter the effects of radiation toxicity, a potential mechanism explaining the resistance of PCSCs to radiotherapy. Finally, in vivo subcutaneous tumor models demonstrate that combination of radiotherapy and EAD1 is the most successful at controlling tumor growth. The models also confirmed a similar toxicity profile between EAD1 and Hydroxychloroquine.

Inhibiting autophagy flux and DNA repair of tumor cells to boost radiotherapy of orthotopic glioblastoma

Radio-resistance of glioblastoma (GBM) remains a leading cause of radiotherapy failure because of the protective autophagy induced by X-Ray irradiation and tumor cells' strong capability of repairing damaged DNA. It is of great importance to overcome the radio-resistance for improving the efficacy of radiotherapy. Herein, we report the novel mechanism of core-shell copper selenide coated gold nanoparticles (Au@Cu_2-xSe NPs) inhibiting the protective autophagy and DNA repair of tumor cells to drastically boost the radiotherapy efficacy of glioblastoma. We reveal that the core-shell Au@Cu_2-xSe NPs can inhibit the autophagy flux by effectively alkalizing lysosomes. They can increase the SQSTM1/p62 protein levels of tumor cells without influencing their mRNA. We also reveal that Au@Cu_2-xSe NPs can increase the ubiquitination of DNA repair protein Rad51, and promote the degradation of Rad51 by proteasomes to prevent the DNA repair. The simultaneous inhibition of protective autophagy and DNA repair significantly suppress the growth of orthotopic GBM by using radiotherapy and our novel Au@Cu_2-xSe NPs. Our work provides a new insight and paradigm to significantly improve the efficacy of radiotherapy by rationally designing theranostic nano-agents to simultaneously inhibit protective autophagy and DNA repair of tumor cells.

MicroRNA expression profiling of sea perch brain cells reveals the roles of microRNAs in autophagy induced by RGNNV infection

Nervous necrosis virus (NNV) is one of the most destructive fish viruses and affects more than 120 marine and freshwater teleost species. However, the pathogenesis of NNV has not been made clear. MicroRNAs (miRNAs) play important roles in the regulation of viral infection. To understand the roles and regulation patterns of miRNAs in NNV infection, high-throughput sequencing was carried out in Lateolabrax japonicus brain (LJB) cells with or without red-spotted grouper NNV (RGNNV) infection at 12 and 24 hr. Here, we identified 59 known and 61 novel differentially expressed miRNAs (DE miRNAs) between mock and RGNNV-infected LJB cells. KEGG pathway analysis showed that the target genes of DE miRNAs were significantly enriched in immune-related signalling pathways, such as autophagy, mitophagy and TGF-beta signalling pathways. The expression patterns of four DE miRNAs (lja-miR-145, lja-miR-182, lja-miR-183 and lja-miR-187) were verified by qRT-PCR both in vivo and in vitro. We found that lja-miR-145 promoted RGNNV proliferation, while lja-miR-183 suppressed RGNNV proliferation. Furthermore, lja-miR-145 facilitated RGNNV-induced autophagy activation, whereas lja-miR-183 repressed autophagy in LJB cells as measured by LC3B-II/I and p62 protein levels. All these results indicate the involvement of lja-miR-145 and lja-miR-183 in RGNNV-induced autophagy. In conclusion, this study provides evidence for the important roles of miRNAs in NNV infection and a basis for uncovering the molecular regulation mechanism of NNV-induced autophagy.

miRNA‑7515 suppresses pancreatic cancer cell proliferation, migration and invasion via downregulating IGF‑1 expression

Pancreatic cancer (PC) is a lethal malignancy of the gastrointestinal tract. Previous studies have reported that microRNAs (miRNAs/miRs) are involved in the tumorigenesis of PC. Therefore, the present study aimed to determine the effects of miR‑7515 on PC cell proliferation, invasion and migration in vitro and in vivo, and investigate its underlying molecular mechanism using bioinformatics, double luciferase assay and western blotting. The results revealed that the expression levels of miR‑7515 were downregulated in PC, which predicted a poor clinical outcome. The overexpression of miR‑7515 significantly decreased the proliferation, invasive and migratory abilities of PC cells in vitro and in vivo, while the knockdown of miR‑7515 exerted the opposite effects. miR‑7515 was identified to directly bind to insulin‑like growth factor 1 (IGF‑1) and downregulate its expression, which subsequently downregulated the Ras/Raf/MEK/ERK signalling pathway. The overexpression of IGF‑1 reversed the inhibitory effects of miR‑7515 overexpression on PC cells. In conclusion, the findings of the present study indicated that miR‑7515 may act as a tumor suppressor in PC, as it repressed PC cell proliferation invasion and migration via downregulating the expression of IGF‑1 and the activity of the Ras/Raf/MEK/ERK signalling pathways.

The interplay of microRNAs and transcription factors in autophagy regulation in nonalcoholic fatty liver disease

The autophagy-lysosomal degradation system has an important role in maintaining liver homeostasis by removing unnecessary intracellular components. Impaired autophagy has been linked to nonalcoholic fatty liver disease (NAFLD), which includes hepatitis, steatosis, fibrosis, and cirrhosis. Thus, gaining an understanding of the mechanisms that regulate autophagy and how autophagy contributes to the development and progression of NAFLD has become the focus of recent studies. Autophagy regulation has been thought to be primarily regulated by cytoplasmic processes; however, recent studies have shown that microRNAs (miRNAs) and transcription factors (TFs) also act as key regulators of autophagy by targeting autophagy-related genes. In this review, we summarize the miRNAs and TFs that regulate the autophagy pathway in NAFLD. We further focus on the transcriptional and posttranscriptional regulation of autophagy and discuss the complex regulatory networks involving these regulators in autophagy. Finally, we highlight the potential of targeting miRNAs and TFs involved in the regulation of autophagy for the treatment of NAFLD.

MicroRNA: a novel implication for damage and protection against ionizing radiation

Ionizing radiation (IR) is a form of high energy. It poses a serious threat to organisms, but radiotherapy is a key therapeutic strategy for various cancers. It is significant to reduce radiation injury but maximize the effect of radiotherapy. MicroRNAs (miRNAs) are posttranscriptionally regulatory factors involved in cellular radioresponse. In this review, we show how miRNAs regulate important genes on cellular response to IR-induced damage and how miRNAs participate in IR-induced carcinogenesis. Additionally, we summarize the experimental and clinical evidence for miRNA involvement in radiotherapy and discuss their potential for improvement of radiotherapy. Finally, we highlight the role that miRNAs play in accident exposure to IR or radiotherapy as predictive biomarker. miRNA therapeutics have shown great perspective in radiobiology; miRNA may become a novel strategy for damage and protection against IR.

The Emerging Roles of Autophagy-Related MicroRNAs in Cancer

Autophagy is a conserved catabolic process involving the degradation and recycling of damaged biomacromolecules or organelles through lysosomal-dependent pathways and plays a crucial role in maintaining cell homeostasis. Consequently, abnormal autophagy is associated with multiple diseases, such as infectious diseases, neurodegenerative diseases and cancer. Currently, autophagy is considered to be a dual regulator in cancer, functioning as a suppressor in the early stage while supporting the growth and metastasis of cancer cells in the later stage and may also produce therapeutic resistance. MicroRNAs (miRNAs) are small, non-coding RNA molecules that regulate gene expression at the post-transcriptional level by silencing targeted mRNA. MiRNAs have great regulatory potential for several fundamental biological processes, including autophagy. In recent years, an increasing number of studies have linked miRNA dysfunction to the growth, metabolism, migration, metastasis, and responses of cancer cells to therapy. Therefore, the study of autophagy-related miRNAs in cancer will provide insights into cancer biology and lead to the development of novel anti-cancer strategies. In the present review, we summarise the current knowledge of miRNA dysregulation during autophagy in cancer, focusing on the relationship between autophagy and miRNAs, and discuss their involvement in cancer biology and cancer treatment.

The Emerging Role of miRNAs for the Radiation Treatment of Pancreatic Cancer

Simple Summary

Pancreatic cancer is an aggressive disease with a high mortality rate. Radiotherapy is one treatment option within a multimodal therapy approach for patients with locally advanced, non-resectable pancreatic tumors. However, radiotherapy is only effective in about one-third of the patients. Therefore, biomarkers that can predict the response to radiotherapy are of utmost importance. Recently, microRNAs, small non-coding RNAs regulating gene expression, have come into focus as there is growing evidence that microRNAs could serve as diagnostic, predictive and prognostic biomarkers in various cancer entities, including pancreatic cancer. Moreover, their high stability in body fluids such as serum and plasma render them attractive candidates for non-invasive biomarkers. This article describes the role of microRNAs as suitable blood biomarkers and outlines an overview of radiation-induced microRNAs changes and the association with radioresistance in pancreatic cancer.

Abstract

Today, pancreatic cancer is the seventh leading cause of cancer-related deaths worldwide with a five-year overall survival rate of less than 7%. Only 15–20% of patients are eligible for curative intent surgery at the time of diagnosis. Therefore, neoadjuvant treatment regimens have been introduced in order to downsize the tumor by chemotherapy and radiotherapy. To further increase the efficacy of radiotherapy, novel molecular biomarkers are urgently needed to define the subgroup of pancreatic cancer patients who would benefit most from radiotherapy. MicroRNAs (miRNAs) could have the potential to serve as novel predictive and prognostic biomarkers in patients with pancreatic cancer. In the present article, the role of miRNAs as blood biomarkers, which are associated with either radioresistance or radiation-induced changes of miRNAs in pancreatic cancer, is discussed. Furthermore, the manuscript provides own data of miRNAs identified in a pancreatic cancer mouse model as well as radiation-induced miRNA changes in the plasma of tumor-bearing mice.

Regulatory effects of noncoding RNAs on the interplay of oxidative stress and autophagy in cancer malignancy and therapy

Noncoding RNAs (ncRNAs) regulation of various diseases including cancer has been extensively studied. Reactive oxidative species (ROS) elevated by oxidative stress are associated with cancer progression and drug resistance, while autophagy serves as an ROS scavenger in cancer cells. However, the regulatory effects of ncRNAs on autophagy and ROS in various cancer cells remains complex. Here, we explore how currently investigated ncRNAs, mainly miRNAs and lncRNAs, are involved in ROS production through modulating antioxidant genes. The regulatory effects of miRNAs and lncRNAs on autophagy-related (ATG) proteins to control autophagy activity in cancer cells are discussed. Moreover, differential expression of ncRNAs in tumor and normal tissues of cancer patients are further analyzed using The Cancer Genome Atlas (TCGA) database. This review hypothesizes links between ATG genes- or antioxidant genes-modulated ncRNAs and ROS production, which might result in tumorigenesis, malignancy, and cancer recurrence. A better understanding of the regulation of ROS and autophagy by ncRNAs might advance the use of ncRNAs as diagnostic and prognostic markers as well as therapeutic targets in cancer therapy.

microRNA-based autophagy inhibition as targeted therapy in pancreatic cancer

Pancreatic cancer is a malignancy with extremely low five-year survival rate. Pancreatic tumors maintain a high basal level of autophagy for survival and progression. Autophagy dysfunction leads to tumor progression in pancreatic cancer patients. Clinical trials with autophagy inhibitors, including hydroxychloroquine and chloroquine, showed no significant therapeutic benefit as monotherapy. Instead of using chemical inhibitors, microRNA may serve as an alternative approach for autophagy inhibition. In the context of pancreatic cancer, the feasibility of using the microRNA approach to target core autophagy-related genes has been shown, which results in suppression of initiation or flux blockage of autophagy. In addition, autophagy inhibition leads to increased sensitivity of pancreatic tumors to a variety of therapeutic approaches, including radiotherapy, chemotherapy and other targeted agents. Recent studies suggest microRNA-based autophagy inhibition can be a promising and feasible approach for the clinical care of pancreatic cancer patients. Here we reviewed the mechanism of autophagy and recent progress of autophagy inhibition in pancreatic cancer treatment. We particularly focus on the microRNA approach in autophagy inhibition in pancreatic cancer.

Could Protons and Carbon Ions Be the Silver Bullets Against Pancreatic Cancer?

Pancreatic cancer is a very aggressive cancer type associated with one of the poorest prognostics. Despite several clinical trials to combine different types of therapies, none of them resulted in significant improvements for patient survival. Pancreatic cancers demonstrate a very broad panel of resistance mechanisms due to their biological properties but also their ability to remodel the tumour microenvironment. Radiotherapy is one of the most widely used treatments against cancer but, up to now, its impact remains limited in the context of pancreatic cancer. The modern era of radiotherapy proposes new approaches with increasing conformation but also more efficient effects on tumours in the case of charged particles. In this review, we highlight the interest in using charged particles in the context of pancreatic cancer therapy and the impact of this alternative to counteract resistance mechanisms.

Non-Coding RNAs in Cancer Radiosensitivity: MicroRNAs and lncRNAs as Regulators of Radiation-Induced Signaling Pathways

Radiotherapy is a cancer treatment that applies high doses of ionizing radiation to induce cell death, mainly by triggering DNA double-strand breaks. The outcome of radiotherapy greatly depends on radiosensitivity of cancer cells, which is determined by multiple proteins and cellular processes. In this review, we summarize current knowledge on the role of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), in determining the response to radiation. Non-coding RNAs modulate ionizing radiation response by targeting key signaling pathways, including DNA damage repair, apoptosis, glycolysis, cell cycle arrest, and autophagy. Additionally, we indicate miRNAs and lncRNAs that upon overexpression or inhibition alter cellular radiosensitivity. Current data indicate the potential of using specific non-coding RNAs as modulators of cellular radiosensitivity to improve outcome of radiotherapy.

Autophagy in cancers including brain tumors: role of MicroRNAs

Autophagy has a crucial role in many cancers, including brain tumors. Several types of endogenous molecules (e.g. microRNAs, AKT, PTEN, p53, EGFR, and NF1) can modulate the process of autophagy. Recently miRNAs (small non-coding RNAs) have been found to play a vital role in the regulation of different cellular and molecular processes, such as autophagy. Deregulation of these molecules is associated with the development and progression of different pathological conditions, including brain tumors. It was found that miRNAs are epigenetic regulators, which influence the level of proteins coded by the targeted mRNAs with any modification of the genetic sequences. It has been revealed that various miRNAs (e.g., miR-7-1-3p, miR-340, miR-17, miR-30a, miR-224-3p, and miR-93), as epigenetic regulators, can modulate autophagy pathways within brain tumors. A deeper understanding of the underlying molecular targets of miRNAs, and their function in autophagy pathways could contribute to the development of new treatment methods for patients with brain tumors. In this review, we summarize the various miRNAs, which are involved in regulating autophagy in brain tumors. Moreover, we highlight the role of miRNAs in autophagy-related pathways in different cancers.

Non-coding RNAs in Pancreatic Ductal Adenocarcinoma

Non-coding RNAs (ncRNAs) are reported to be expressed in human cancers, including pancreatic ductal adenocarcinoma (PDAC). These ncRNAs affect the growth, migration and invasion of tumor cells by regulating cell cycle and apoptosis, as well as playing important roles in epigenetic processes, transcription and post-transcriptional regulation. It is still unclear whether alterations in ncRNAs influence PDAC development and progression. Because of this, analysis based on existing data on ncRNAs, which are crucial for modulating pancreatic tumorigenesis, will be important for future research on PDAC. Here, we summarize ncRNAs with tumor-promoting functions: HOTAIR, HOTTIP, MALAT1, lncRNA H19, lncRNA PVT1, circ-RNA ciRS-7, circ-0030235, circ-RNA_100782, circ-LDLRAD3, circ-0007534, circRHOT1, circZMYM2, circ-IARS, circ-RNA PDE8A, miR-21, miR-155, miR-221/222, miR-196b, miR-10a. While others including GAS5, MEG3, and lncRNA ENST00000480739, has_circ_0001649, miR-34a, miR-100, miR-217, miR-143 inhibit the proliferation and invasion of PDAC. Hence, we summarize the functions of ncRNAs in the occurrence, development and metastasis of PDAC, with the goal to provide guidance in the clinical diagnosis and treatment of PDAC.

MicroRNAs as major regulators of the autophagy pathway

Autophagy is a cellular stress response mechanism activation of which leads to degradation of cellular components, including proteins as well as damaged organelles in lysosomes. Defects in autophagy mechanisms were associated with several pathologies (e.g. cancer, neurodegenerative diseases, and rare genetic diseases). Therefore, autophagy regulation is under strict control. Transcriptional and post-translational mechanisms that control autophagy in cells and organisms studied in detail. Recent studies introduced non-coding small RNAs, and especially microRNAs (miRNAs) in the post-translational orchestration of the autophagic activity. In this review article, we analyzed in detail the current status of autophagy-miRNA connections. Comprehensive documentation of miRNAs that were directly involved in autophagy regulation resulted in the emergence of common themes and concepts governing these complex and intricate interactions. Hence, a better and systematic understanding of these interactions reveals a central role for miRNAs in the regulation of autophagy.

Clinical value of circular RNAs and autophagy-related miRNAs in the diagnosis and treatment of pancreatic cancer

BACKGROUND

Circular RNAs (circRNAs) are a special group of long-chain and non-coding RNAs characterized by a closed-loop structure without 3' and 5' polarity. In recent years, studies have demonstrated that circRNAs act as microRNA (miRNA) sponges to regulate the function of miRNAs. Increasing evidence indicates that circRNAs and targeted miRNAs are involved in the development, progression and metastasis of various cancers and drug resistance. A number of miRNAs are known to be associated with the pathogenesis, development and treatment of pancreatic cancer by regulating the autophagic activity.

DATA SOURCES

A comprehensive literature search was executed in PubMed and EMBASE using the medical subject headings (MeSH) terms "Pancreatic Neoplasms", "autophagy", "RNA, circular" and "microRNA". We also used text terms such as "diagnosis", "prognosis" and "biomarker" to supplement the results.

RESULTS

Autophagy-related miRNAs is closely related to pancreatic cancer. On basis of the retrieval results, we summarized the synthesis, features and functions of circRNAs and analyzed the association between autophagy-related miRNAs and pancreatic cancer.

CONCLUSIONS

circRNAs act as the miRNA sponges and there is an association between miRNAs and autophagy, which provides a new concept to broaden the knowledge about the mechanisms underlying the development, progression and metastasis of pancreatic cancer. Additionally, clinical value of circRNAs and autophagy-related miRNAs in the diagnosis and treatment of pancreatic cancer would be further verified with in-depth researches.

microRNAs: Potential glioblastoma radiosensitizer by targeting radiation-related molecular pathways

Glioblastoma (GBM) is the most lethal type of primary brain tumor. Currently, even with optimal and multimodal cancer therapies, the survival rate of GBM patients remains poor. One reason for inadequate response of GBM tumors to radiotherapy is radioresistance (RR). Thus, there is a critical need for new insights about GBM treatment to increase the chance of treatment. microRNAs (miRNAs) are important regulatory molecules that can effectively control GBM radiosensitivity (RS) by affecting radiation-related signal transduction pathways such as apoptosis, proliferation, DNA repair and cell cycle regulation. miRNAs provide new clinical perspectives for developing effective GBM treatments. A growing body of literature has demonstrated that GBM RS can be modified by modulating the expression of miRNAs such as miR-7, miR-10b, miR-124, miR-128, miR-320, miR-21, miR-203, and miR-153. This paper highlights the miRNAs and the underlying molecular mechanisms that are involved in the RS of GBM. Besides highlighting the role of miRNAs in different signaling pathways, we explain the mechanisms that affect RS of GBM for modulating radiation response at the clinical level.

Overexpression of microRNA-216a inhibits autophagy by targeting regulated MAP1S in colorectal cancer

Background: Autophagy executes the rapid degradation of unneeded proteins and organelles through the lysosomal pathway, and is a crucial catabolic process widely conserved among eukaryotes. miRNAs can modulate autophagy by targeting genes encoding proteins involved in the process. A great deal of researchhas indicated that miR-216a was a functional miRNA related to tumorigenesis. However, the contribution of miR-216a to autophagy in colorectal cancer (CRC) remains unclear. The purpose of this study was to investigate the role of miR-216a in autophagy in CRC cells. Methods: The expression levels of miR-216a in 67 paired CRC patients were evaluated by qRT-PCR. Direct gene targeting predicted by TargetScan and miRanda was confirmed by luciferase activity. Western blot and flow cytometry were used to identify the regulatory mechanism of miR-216a on autophagy in CRC cells. Results: We determined that miR-216a is downregulated in CRC by screening its expression in 67 CRC tissue samples. Dual luciferase reporter assays showed that miR-216a binds the 3'-UTR of MAP1S, suggesting that MAP1S is a direct target of miR-216a. miR-216a could inhibit autophagy in HCT-116 and HT-29 CRC cells through downregulating MAP1S expression. Flow cytometry and Western blot analysis demonstrated that overexpression of miR-216a reduced MAP1S mRNA and protein levels. Moreover, we determined that miR-216a-regulated inhibition of autophagy via MAP1S regulation involves the TGF-β pathway. Conclusion: Taken together, our findings indicate that miR-216a was a tumor-suppressor miRNA in human CRC, which can inhibit autophagy via the TGF-β/MAP1S pathway.

MicroRNA-mediated redox regulation modulates therapy resistance in cancer cells: clinical perspectives

BACKGROUND

Chemotherapy and radiation therapy are the most common types of cancer therapy. The development of chemo/radio-resistance remains, however, a major obstacle. Altered redox balances are among of the main factors mediating therapy resistance. Therefore, redox regulatory strategies are urgently needed to overcome this problem. Recently, microRNAs have been found to act as major redox regulatory factors affecting chemo/radio-resistance. MicroRNAs play critical roles in regulating therapeutic resistance through the regulation of antioxidant enzymes, redox-sensitive signaling pathways, cancer stem cells, DNA repair mechanisms and autophagy.

CONCLUSIONS

Here, we summarize current knowledge on microRNA-mediated redox regulatory mechanisms underlying chemo/radio-resistance. This knowledge may form a basis for a better clinical management of cancer patients.

LncRNA DANCR Promotes Lung Cancer by Sequestering miR-216a

BACKGROUND

Long noncoding RNAs (lncRNAs) are a new class of cancer regulators. Here, we aimed to investigate the diagnostic and therapeutic values of an lncRNA, differentiation antagonizing noncoding RNA (DANCR), in lung cancer.

METHODS

Real-time polymerase chain reaction was used to compare DANCR levels in normal and cancerous lung tissues as well as lung cancer cells. Lentiviral transduction was used to induce DANCR overexpression or silencing in vitro, followed by monitoring cell proliferation, colony formation, and changes in microRNA-216a (miR-216a) expression. DANCR-specific small hairpin RNA transduction was used to establish cells with stable DANCR knockdown, and silenced cells were used to initiate lung tumor xenografts, followed by monitoring tumor growth.

RESULTS

DANCR upregulation was seen in lung cancer, particularly in high-grade lung cancer tissues and aggressive cancer cells. Ectopic DANCR expression induced lung cancer cell proliferation and colony formation, whereas DANCR silencing induced opposing effects. The miR-216a level in cancer cells was negatively correlated with DANCR expression. The DANCR knockdown reduced the growth of tumor xenografts in vivo.

CONCLUSION

DANCR upregulation is a potential indicator of aggressive lung cancer. Silencing of DANCR has great potential as a potent therapeutic strategy in lung cancer.

MicroRNAs in Cardiac Autophagy: Small Molecules and Big Role

Autophagy, which is an evolutionarily conserved process according to the lysosomal degradation of cellular components, plays a critical role in maintaining cell homeostasis. Autophagy and mitochondria autophagy (mitophagy) contribute to the preservation of cardiac homeostasis in physiological settings. However, impaired or excessive autophagy is related to a variety of diseases. Recently, a close link between autophagy and cardiac disorders, including myocardial infarction, cardiac hypertrophy, cardiomyopathy, cardiac fibrosis, and heart failure, has been demonstrated. MicroRNAs (miRNAs) are a class of small non-coding RNAs with a length of approximately 21–22 nucleotides (nt), which are distributed widely in viruses, plants, protists, and animals. They function in mediating the post-transcriptional gene silencing. A growing number of studies have demonstrated that miRNAs regulate cardiac autophagy by suppressing the expression of autophagy-related genes in a targeted manner, which are involved in the pathogenesis of heart diseases. This review summarizes the role of microRNAs in cardiac autophagy and related cardiac disorders. Furthermore, we mainly focused on the autophagy regulation pathways, which consisted of miRNAs and their targeted genes.

Reduced Autophagy by a microRNA-mediated Signaling Cascade in Diabetes-induced Renal Glomerular Hypertrophy

Autophagy plays a key role in the pathogenesis of kidney diseases, however its role in diabetic nephropathy (DN), and particularly in kidney glomerular mesangial cells (MCs) is not very clear. Transforming Growth Factor- β1 (TGF-β), a key player in the pathogenesis of DN, regulates expression of various microRNAs (miRNAs), some of which are known to regulate the expression of autophagy genes. Here we demonstrate that miR-192, induced by TGF-β signaling, plays an important role in regulating autophagy in DN. The expression of key autophagy genes was decreased in kidneys of streptozotocin-injected type-1 and type-2 (db/db) diabetic mice and this was reversed by treatment with Locked Nucleic Acid (LNA) modified miR-192 inhibitors. Changes in autophagy gene expression were also attenuated in kidneys of diabetic miR-192-KO mice. In vitro studies using mouse glomerular mesangial cells (MMCs) also showed a decrease in autophagy gene expression with TGF-β treatment. miR-192 mimic oligonucleotides also decreased the expression of certain autophagy genes. These results demonstrate that TGF-β and miR-192 decrease autophagy in MMCs under diabetic conditions and this can be reversed by inhibition or deletion of miR-192, further supporting miR-192 as a useful therapeutic target for DN.

Role of metabolism in cancer cell radioresistance and radiosensitization methods

BACKGROUND

Radioresistance is a major factor leading to the failure of radiotherapy and poor prognosis in tumor patients. Following the application of radiotherapy, the activity of various metabolic pathways considerably changes, which may result in the development of resistance to radiation.

MAIN BODY

Here, we discussed the relationships between radioresistance and mitochondrial and glucose metabolic pathways, aiming to elucidate the interplay between the tumor cell metabolism and radiotherapy resistance. In this review, we additionally summarized the potential therapeutic targets in the metabolic pathways.

SHORT CONCLUSION

The aim of this review was to provide a theoretical basis and relevant references, which may lead to the improvement of the sensitivity of radiotherapy and prolong the survival of cancer patients.

Upregulation of miR-216a exerts neuroprotective effects against ischemic injury through negatively regulating JAK2/STAT3-involved apoptosis and inflammatory pathways

OBJECTIVE

Ischemic stroke remains a significant cause of death and disability in industrialized nations. Janus tyrosine kinase (JAK) and signal transducer and activator of transcription (STAT) of the JAK2/STAT3 pathway play important roles in the downstream signal pathway regulation of ischemic stroke-related inflammatory neuronal damage. Recently, microRNAs (miRNAs) have emerged as major regulators in cerebral ischemic injury; therefore, the authors aimed to investigate the underlying molecular mechanism between miRNAs and ischemic stroke, which may provide potential therapeutic targets for ischemic stroke.

METHODS

The JAK2- and JAK3-related miRNA (miR-135, miR-216a, and miR-433) expression levels were detected by real-time quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) and Western blot analysis in both oxygen-glucose deprivation (OGD)-treated primary cultured neuronal cells and mouse brain with middle cerebral artery occlusion (MCAO)-induced ischemic stroke. The miR-135, miR-216a, and miR-433 were determined by bioinformatics analysis that may target JAK2, and miR-216a was further confirmed by 3' untranslated region (3'UTR) dual-luciferase assay. The study further detected cell apoptosis, the level of lactate dehydrogenase, and inflammatory mediators (inducible nitric oxide synthase [iNOS], matrix metalloproteinase-9 [MMP-9], tumor necrosis factor-α [TNF-α], and interleukin-1β [IL-1β]) after cells were transfected with miR-NC (miRNA negative control) or miR-216a mimics and subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) damage with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, annexin V-FITC/PI, Western blots, and enzyme-linked immunosorbent assay detection. Furthermore, neurological deficit detection and neurological behavior grading were performed to determine the infarction area and neurological deficits.

RESULTS

JAK2 showed its highest level while miR-216a showed its lowest level at day 1 after ischemic reperfusion. However, miR-135 and miR-433 had no obvious change during the process. The luciferase assay data further confirmed that miR-216a can directly target the 3'UTR of JAK2, and overexpression of miR-216a repressed JAK2 protein levels in OGD/R-treated neuronal cells as well as in the MCAO model ischemic region. In addition, overexpression of miR-216a mitigated cell apoptosis both in vitro and in vivo, which was consistent with the effect of knockdown of JAK2. Furthermore, the study found that miR-216a obviously inhibited the inflammatory mediators after OGD/R, including inflammatory enzymes (iNOS and MMP-9) and cytokines (TNF-α and IL-1β). Upregulating miR-216a levels reduced ischemic infarction and improved neurological deficit.

CONCLUSIONS

These findings suggest that upregulation of miR-216a, which targets JAK2, could induce neuroprotection against ischemic injury in vitro and in vivo, which provides a potential therapeutic target for ischemic stroke.

MicroRNA as a Therapeutic Target in Cardiac Remodeling

MicroRNAs (miRNAs) are small RNA molecules that contain 18–25 nucleotides. The alterations in their expression level play crucial role in the development of many disorders including heart diseases. Myocardial remodeling is the final pathological consequence of a variety of myocardial diseases. miRNAs have central role in regulating pathogenesis of myocardial remodeling by modulating cardiac hypertrophy, cardiomyocytes injury, cardiac fibrosis, angiogenesis, and inflammatory response through multiple mechanisms. The balancing and tight regulation of different miRNAs is a key to drive the cellular events towards functional recovery and any fall in this leads to detrimental effect on cardiac function following various insults. In this review, we discuss the impact of alterations of miRNAs expression on cardiac hypertrophy, cardiomyocytes injury, cardiac fibrosis, angiogenesis, and inflammatory response. We have also described the targets (receptors, signaling molecules, transcription factors, etc.) of miRNAs on which they act to promote or attenuate cardiac remodeling processes in different type cells of cardiac tissues.

CISD2 promotes the proliferation of glioma cells via suppressing beclin‑1‑mediated autophagy and is targeted by microRNA‑449a

CDGSH iron sulfur domain 2 (CISD2) has been found to be important in carcinogenesis. However, the role of CISD2 in glioma remains to be elucidated. The present study aimed to investigate the role of CISD2 in glioma using the reverse transcription-quantitative polymerase chain reaction, western blotting, co-immunoprecipitation assay, immunofluorescence staining and other methods. The results demonstrated that the mRNA and protein levels of CISD2 were found to be upregulated in glioma tissues, compared with the levels in matched normal tissues. Clinical data analysis showed that the level of CISD2 was negatively correlated with the survival rates of patients with glioma. In addition, high levels of CISD2 were associated with advanced clinical stage, relapse, vascular invasion and increased tumor size. The inhibition of CISD2 suppressed the proliferation and survival of glioma cells in vitro and in vivo. Mechanistically, it was found that small interfering RNA-induced knock down of CISD2 inhibited the proliferation of glioma cells through activating beclin-1-mediated autophagy. The results also revealed that CISD2 was a target of microRNA (miR)-449a. Together, the results of the present study demonstrated that CISD2 was increased in glioma samples and was associated with poor prognosis and aggressive tumor behavior. The miR-449a/CISD2/beclin-1-mediated autophagy regulatory network contributed to the proliferation of glioma cells. Targeting this pathway may be a promising strategy for glioma therapy.

Regulation of Autophagy by MiRNAs and Their Emerging Roles in Tumorigenesis and Cancer Treatment

Autophagy is a conserved catabolic process for the degradation and recycling of cytosolic components or organelles through a lysosome-dependent pathway. Autophagy can be induced in response to multiple stress conditions, such as nutrient deprivation, hypoxia, energy depletion, etc. As a result, autophagy can regulate many biological processes, including cell survival, metabolism, differentiation, senescence, and cell death. MicroRNAs (MiRNAs) are small noncoding molecules that regulate gene expression by silencing mRNA targets. MiRNA dysregulation exhibits great regulatory potential during organismal development, hematopoiesis, immunity, cell proliferation and death, and autophagy. Recently, increasing studies have linked MiRNAs to autophagic regulation during cancer initiation and development. Although the relationship between MiRNAs and autophagy is quite complicated and has not been well elucidated, MiRNAs may underlie key aspects of autophagy and cancer biology. Increasing evidence shows that MiRNAs play important roles as both oncogenic MiRNAs and tumor suppressive MiRNAs in cancer initiation and development. Thus, understanding the novel relationship between MiRNAs and autophagy may allow us to develop promising cancer biomarkers and therapeutic targets.

Genomic Variations in Pancreatic Cancer and Potential Opportunities for Development of New Approaches for Diagnosis and Treatment

Human pancreatic cancer has a very poor prognosis with an overall five-year survival rate of less than 5% and an average median survival time of six months. This is largely due to metastatic disease, which is already present in the majority of patients when diagnosed. Although our understanding of the molecular events underlying multi-step carcinogenesis in pancreatic cancer has steadily increased, translation into more effective therapeutic approaches has been inefficient in recent decades. Therefore, it is imperative that novel and targeted approaches are designed to facilitate the early detection and treatment of pancreatic cancer. Presently, there are numerous ongoing studies investigating the types of genomic variations in pancreatic cancer and their impact on tumor initiation and growth, as well as prognosis. This has led to the development of therapeutics to target these genetic variations for clinical benefit. Thus far, there have been minimal clinical successes directly targeting these genomic alterations; however research is ongoing to ultimately discover an innovative approach to tackle this devastating disease. This review will discuss the genomic variations in pancreatic cancer, and the resulting potential diagnostic and therapeutic implications.

miR-155 Promotes ox-LDL-Induced Autophagy in Human Umbilical Vein Endothelial Cells

As an evolutionarily conserved metabolic process, autophagy is involved in the process of atherosclerosis (AS). MicroRNA-155 (miR-155), a multifunctional miRNA, plays an important role in many physiological and pathological conditions, including AS and autophagy. However, the effect of miR-155 on the regulation of autophagy in endothelial cells has not been reported to date. Therefore, the objective of our study was to investigate the role of miR-155 in autophagy induced by oxidized low-density lipoprotein (ox-LDL) in human umbilical vein endothelial cells (HUVECs). Our results demonstrated that ox-LDL induced autophagy in HUVECs and increased the expression of miR-155 significantly. Overexpression of miR-155 improved autophagic activity, whereas low expression of miR-155 inhibited autophagic activity. Therefore, the data demonstrated that miR-155 has a modulating effect on the autophagy of vascular endothelial cells.

Enhanced Autophagy Contributes to Protective Effects of GM1 Ganglioside Against Aβ1-42-Induced Neurotoxicity and Cognitive Deficits

Alzheimer's disease (AD) is a progressive neurodegenerative disorder. The aggregation of Aβ peptides, Aβ1-42 in particular, is thought to be a fundamental pathogenic mechanism leading to the neuronal damage in AD. Recently, monosialoganglioside GM1 is reported to possess pivotal neuroprotection in neurodegenerative diseases. Previous studies have focused on the conformational dynamics and the biochemical interaction of the amyloid-peptide with the GM1 ganglioside, as well as the protective effect of GM1 on cognition. However, the phenomenon of autophagy with regard to neuronal dysfunction in AD is less investigated. In the present study, GM1 treatment were investigated in an AD mouse model and cultured PC12 dells to examine cognition-protective and neuroprotective effects of GM1. Furthermore, GM1 was found to induce autophagy via testing light chain 3 (LC3), Beclin1, neighbor of BRCA1 gene 1 protein and p62 (a substrate of LC3). Chloroquine, an inhibitor of lysosomal, was used to exclude the interference of lysosome, which could fuse with autophagosome and then clear it. In the presence of the inhibitor of autophagy (3-methyladenine; 3-MA), the protective effect of GM1 on PC12 cells in Aβ (1-42) induced toxic conditions was diminished. Interestingly, the expression of histone deacetylase 1 was increased in PC12 cells when treated with GM1, indicating that autophagy might be activated by GM1 through a pathway integrates protein acetylation. This study provides a novel insight into the protective role of GM1 against Aβ (1-42)-induced neurotoxicity via enhancing autophagy.

Autophagy-Regulating microRNAs and Cancer

Macroautophagy (autophagy herein) is a cellular stress response and a survival pathway that is responsible for the degradation of long-lived proteins, protein aggregates, as well as damaged organelles in order to maintain cellular homeostasis. Consequently, abnormalities of autophagy are associated with a number of diseases, including Alzheimers’s disease, Parkinson’s disease, and cancer. According to the current view, autophagy seems to serve as a tumor suppressor in the early phases of cancer formation, yet in later phases, autophagy may support and/or facilitate tumor growth, spread, and contribute to treatment resistance. Therefore, autophagy is considered as a stage-dependent dual player in cancer. microRNAs (miRNAs) are endogenous non-coding small RNAs that negatively regulate gene expression at a post-transcriptional level. miRNAs control several fundamental biological processes, and autophagy is no exception. Furthermore, accumulating data in the literature indicate that dysregulation of miRNA expression contribute to the mechanisms of cancer formation, invasion, metastasis, and affect responses to chemotherapy or radiotherapy. Therefore, considering the importance of autophagy for cancer biology, study of autophagy-regulating miRNA in cancer will allow a better understanding of malignancies and lead to the development of novel disease markers and therapeutic strategies. The potential to provide study of some of these cancer-related miRNAs were also implicated in autophagy regulation. In this review, we will focus on autophagy, miRNA, and cancer connection, and discuss its implications for cancer biology and cancer treatment.

Overexpression of FoxO3a is associated with glioblastoma progression and predicts poor patient prognosis

Forkhead transcription factor FoxO3a has been reported to have ambiguous functions and distinct mechanisms in various solid tumors, including glioblastoma (GBM). Although a preliminary analysis of a small sample of patients indicated that FoxO3a aberrations in glioma might be related to aggressive clinical behavior, the clinical significance of FoxO3a in glioblastoma remains unclear. We investigated the expression of FoxO3a in a cohort of 91 glioblastoma specimens and analyzed the correlations of protein expression with patient prognosis. Furthermore, the functional impact of FoxO3a on GBM progression and the underlying mechanisms of FoxO3a regulation were explored in a series of in vitro and in vivo assays. FoxO3a expression was elevated in glioblastoma tissues, and high nuclear FoxO3a expression in human GBM tissues was associated with poor prognosis. Moreover, knockdown of FoxO3a significantly reduced the colony formation and invasion ability of GBM cells, whereas overexpression of FoxO3a promoted the colony formation and invasion ability. The results of in vivo GBM models further confirmed that FoxO3a knockdown inhibited GBM progression. More, the pro-oncogenic effects of FoxO3a in GBM were mediated by the activation of c-Myc, microtubule-associated protein 1 light chain 3 beta (LC3B) and Beclin1 in a mixed-lineage leukemia 2 (MLL2)-dependent manner. These findings suggest that high FoxO3a expression is associated with glioblastoma progression and that FoxO3a independently indicates poor prognosis in patients. FoxO3a might be a novel prognostic biomarker or a potential therapeutic target in glioblastoma.