Prognostic significance of autophagy-related protein expression in resected pancreatic ductal adenocarcinoma

Co-inhibition of RAGE and TLR4 sensitizes pancreatic cancer to irreversible electroporation in mice by disrupting autophagy

Irreversible electroporation (IRE) is a local ablative treatment for patients with pancreatic cancer. During the IRE procedure, high-intensity electric pulses are released intratumorally to disrupt plasma membranes and induce cell death. Since the intensity of the pulsed electric field (PEF) can be decreased by the tumor microenvironment, some cancer cells are subjected to a sublethal PEF and may survive to cause tumor recurrence later. Autophagy activation induced by anticancer therapies is known to promote treatment resistance. In this study, we investigated whether autophagy is activated in residual cancer cells after IRE and assessed the roles it plays during tumor recurrence. Subcutaneous KPC-A548 or Panc02 murine pancreatic cancer cell line xenograft mouse models were established; once the tumors reached 7 mm in one dimension, the tumor-bearing mice were subjected to IRE. For in vitro sublethal PEF treatment, the pancreatic cancer cell suspension was in direct contact with the electrodes and pulsed at room temperature. We showed that autophagy was activated in surviving residual cells, as evidenced by increased expression of LC3 and p62. Suppression of autophagy with hydroxychloroquine (60 mg/kg, daily intraperitoneal injection) markedly increased the efficacy of IRE. We demonstrated that autophagy activation can be attributed to increased expression of high-mobility group box 1 (HMGB1); co-inhibition of two HMGB1 receptors, receptor for advanced glycosylation end products (RAGE) and Toll-like receptor 4 (TLR4), suppressed autophagy activation by upregulating the PI3K/AKT/p70 ribosomal S6 protein kinase (p70S6K) axis and sensitized pancreatic cancer cells to PEF. We prepared a polymeric micelle formulation (M-R/T) encapsulating inhibitors of both RAGE and TLR4. The combination of IRE and M-R/T (equivalent to RAGE inhibitor at 10.4 mg/kg and TLR4 inhibitor at 5.7 mg/kg, intravenous or intraperitoneal injection every other day) significantly promoted tumor apoptosis, suppressed cell cycle progression, and prolonged animal survival in pancreatic tumor models. This study suggests that disruption of HMGB1-mediated autophagy with nanomedicine is a promising strategy to enhance the response of pancreatic cancer to IRE.

Mechanistic insights and therapeutic strategies for targeting autophagy in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is characterised by early metastasis and resistance to anti-cancer therapy, leading to an overall poor prognosis. Macroautophagy (hereinafter referred to as autophagy) is a conserved cellular homeostasis mechanism that degrades various cargoes (e.g., proteins, organelles, and pathogens) mainly playing a role in promoting survival under environmental stress. Autophagy is an essential defense mechanism against PDAC initiation, acting on multiple levels to maintain cellular and tissue homeostasis. However, autophagy is also intimately involved in the molecular mechanisms driving PDAC progression, facilitating the adaptation of cancer cells to the tumor microenvironment's harsh conditions. In this review, we examine the complex role of autophagy in PDAC and assess the potential of modulating autophagy as a therapeutic strategy. By reviewing current research and clinical trials, we seek to elucidate how targeting autophagy can disrupt PDAC tumor survival mechanisms, enhance the efficacy of existing treatments, and ultimately improve patient outcomes.

Niraparib perturbs autophagosome-lysosome fusion in pancreatic ductal adenocarcinoma and exhibits anticancer potential against gemcitabine-resistant PDAC

While poly (adenosine diphosphate-ribose) polymerase inhibitors (PARPi) have achieved specific clinical benefits in a subset of pancreatic ductal adenocarcinoma (PDAC) patients, the potential role of the PARPi niraparib in PDAC necessitates further exploration. In this study, we demonstrated that Niraparib exhibited a pronounced inhibitory effect on autophagy in PDAC both in vitro and in vivo. Mechanistically, this inhibition was primarily attributed to niraparib's ability to disrupt the fusion process between autophagosomes and lysosomes, while potentially exerting a relatively minor impact on the initial stage of autophagy. The blockade effect observed may be mediated via modulation of the ERK signaling pathway, and this effect can be mitigated by the application of an ERK inhibitor (FR180204). Notably, the combined treatment regimen of niraparib and gemcitabine failed to elicit the anticipated synergistic effects in wild-type PANC-1 cells, instead exhibiting pronounced antagonistic interactions. However, in gemcitabine-resistant PANC-1 cells, the combination of niraparib and gemcitabine exhibited modest additive effects. Furthermore, niraparib demonstrated a heightened cytotoxic potency against gemcitabine-resistant PANC-1 cells compared to wild-type PANC-1 cells, both in vitro and in vivo. Our research established that niraparib inhibits late-stage autophagy in PDAC, potentially representing a valuable salvage therapy for gemcitabine-resistant PDAC. Further clinical studies are justified.

AMBRA1 drives gastric cancer progression through regulation of tumor plasticity

Background

Stomach adenocarcinoma (STAD) is an aggressive malignancy characterized by high tumor plasticity and heterogeneity. This study investigates the role of Autophagy and Beclin 1 Regulator 1 (AMBRA1) in regulating tumor plasticity in STAD progression.

Methods

Combined with clinical data, the pan-cancer analysis of AMBRA1 was performed to analyze the role of AMBRA1 in STAD. Western blot, Flow Cytometry (FCM) assay, trans-well assay, wound healing assay, MTT, Reactive Oxygen Species (ROS) assay, Reverse Transcription Quantitative Polymerase Chain Reaction (RT-qPCR) and staining were performed to study the effects of AMBRA1 in AGS human gastric cancer cells. An AGS gastric cancer xenograft model was constructed to further verify the role of AMBRA1 in the development of STAD.

Results

AMBRA1 overexpression correlated with poor overall survival in STAD and was positively associated with T cell CD4+ infiltration. High AMBRA1 expression also indicated worse prognosis in patients with high cancer-associated fibroblast infiltration. AMBRA1 depletion suppressed STAD cell proliferation, migration, and invasion in vitro. Mechanistically, AMBRA1 knockdown induced G1/S cell cycle arrest and triggered cellular senescence through epigenetic alterations, including changes in H3K9me3 levels. AMBRA1 inhibition also sensitized STAD cells to chemotherapeutic agents. In vivo studies confirmed the tumor-suppressive effects of AMBRA1 loss, resulting in reduced tumor growth and increased cellular senescence.

Conclusions

Our findings uncover an oncogenic role for AMBRA1 in STAD. Targeting AMBRA1 may induce tumor cell senescence, apoptosis, and potentiate anti-tumor immunity, providing a rationale for developing AMBRA1-targeted precision therapies to improve clinical outcomes in STAD patients.

Ambra1 in cancer: implications for clinical oncology

Activating molecule in Beclin-1-regulated autophagy protein 1 (Ambra1) is well known to mediate the autophagy process and promote the formation of autophagosomes. In addition, Ambra1 is involved in the execution of apoptosis. A growing number of studies have revealed that this protein modifies the sensitivity of cancer cells to anticancer drugs by controlling the balance between autophagy and apoptosis. In addition, Ambra1 is a key factor in regulating the cell cycle, proliferation, invasion and migration. Therefore, it plays a key role in tumorigenesis and progression. Moreover, Ambra1 is highly expressed in a variety of cancers and is closely related to the prognosis of patients. Thus, it appears that Ambra1 has multiple roles in tumorigenesis and progression, which may have implications for clinical oncology. The present review focuses on recent advances in the study of Ambra1, especially the role of the protein in tumorigenesis, progression and effects on anticancer drug sensitivity.

High expression of p62/SQSTM1 predicts shorter survival for patients with pancreatic cancer

BACKGROUND

Accumulation of the signal adaptor protein p62 has been demonstrated in many forms of cancer, including pancreatic ductal adenocarcinoma (PDAC). Although data from experimental studies suggest that p62 accumulation accelerates the development of PDAC, the association between p62 protein expression and survival in PDAC patients is unclear.

METHODS

Thirty-three tumor specimens from PDAC patients treated by primary surgery were obtained. Immunohistochemical expression of p62, microtubule-associated protein 1A/1B-light chain 3 (LC3), and nuclear factor-erythroid factor 2-related factor 2 (NRF2) in tumor tissue was examined for associations with clinicopathological characteristics and disease-specific survival (DSS).

RESULTS

There was no association between p62 expression and any of the clinicopathological variables. However, high p62 protein expression in tumor cells was significantly associated with shorter DSS (7 months vs. 29 months, p = 0.017). The hazard ratio for death in patients with high p62 protein expression in tumor cells was 2.88 (95% confidence interval: 1.17-7.11, p = 0.022). In multivariable analysis, high p62 expression was an independent prognostic factor for shorter DSS (p = 0.020) when follow up time was more than 5 years. LC3 and NRF2 staining was not associated with survival or other clinicopathological parameters.

CONCLUSION

Our results show that high p62 protein expression in tumor cells is associated with shorter survival following pancreatic tumor resection. This association supports a role for p62 as a prognostic marker in patients with PDAC treated by primary surgery.

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.

Sequestsome-1/p62-targeted small molecules for pancreatic cancer therapy

Pancreatic ductal adenocarcinoma (PDAC) is characterized by heightened autophagy and systemic immune dysfunction. Modest improvements in clinical outcomes have been demonstrated in completed clinical trials targeting autophagy with combination hydroxychloroquine (HCQ) and chemotherapy. Recent mechanistic insights into the role of autophagy-dependent immune evasion have prompted the need for more precise and druggable targets of autophagy inhibition. Sequestosome-1 (SQSTM-1) is a multidomain scaffold protein with well-established roles in autophagy, tumor necrosis factor alpha (TNFα)- and NF-κB-related signaling pathways. SQSTM1 overexpression is frequently observed in PDAC, correlating with clinical stage and outcome. Given the unique molecular structure of SQSTM-1 and its diverse activity, identifying means of limiting SQSTM-1-dependent autophagy to promote an effective immune response in PDAC could be a promising treatment strategy.

Development of an Autophagy-Based and Stemness-Correlated Prognostic Model for Hepatocellular Carcinoma Using Bulk and Single-Cell RNA-Sequencing

Accumulating evidence has proved that autophagy serves as a tumor promoter in formed malignancies, and the autophagy-related prognostic signatures have been constructed as clinical tools to predict prognosis in many high-mortality cancers. Autophagy-related genes have participated in the development and metastasis of hepatocellular carcinoma (HCC), but the understanding of their prognostic value is limited. Thereafter, LIMMA and survival analysis were conducted in both ICGC and TCGA databases and a total of 10 hub autophagy-related genes, namely, NPC1, CDKN2A, RPTOR, SPHK1, HGS, BIRC5, SPNS1, BAK1, ATIC, and MAPK3, were collected. Then, GO, KEGG, correlation, consensus, and PCA analyses were utilized to reveal their potential targeted role in HCC treatment. Single-cell RNA-seq of cancer stem cells also indicated that there was a positive correlation between these genes and stemness. In parallel, we applied univariate, LASSO, and multivariate regression analyses to study the autophagy-related genes and finally proposed that ATIC and BIRC5 were the valuable prognostic indicators of HCC. The signature based on ATIC and BIRC5 exhibited moderate power for predicting the survival of HCC in the ICGC cohort, and its efficacy was further validated in the TCGA cohort. Taken together, we suggested that 10 aforementioned hub genes are promising therapeutic targets of HCC and the ATIC/BIRC5 prognostic signature is a practical prognostic indicator for HCC patients.

Prognostic Value of LC3B and p62 Expression in Small Intestinal Adenocarcinoma

Autophagy, a mechanism that maintains cellular homeostasis, is involved in tumor cell growth and survival in cancer, and autophagy inhibitors have been tested clinical trials for anticancer therapy. To elucidate the clinical and prognostic implications of autophagy in small intestinal adenocarcinoma (SIAC), we assessed the expression of autophagy markers, LC3B and p62, in 171 surgically resected primary SIACs using automated quantitative analysis. Positive LC3B, p62 nuclear (p62^Nu), and p62 cytoplasmic (p62^Cy) expression was observed in 23 (13.5%), 52 (30.4%), and 43 (25.1%) carcinomas, respectively. LC3B+ expression was correlated with undifferentiated carcinoma (p < 0.001) and high histologic grade (p = 0.029). The combined expression of LC3B and p62^Nu (LC3+/p62^Nu+) was related to the older age of patients (p = 0.017), undifferentiated carcinoma (p < 0.001), and high grade (p = 0.031). LC3B+ (p = 0.006), p62^Cy+ (p = 0.041), or p62^Nu+ (p = 0.006) expression were associated with worse survival. In addition, SIAC patients with either LC3B+/p62^Nu+ (p = 0.001) or LC3B+/p62^Cy+ (p = 0.002) expression had shorter survival times. In multivariate analysis, LC3B expression remained an independent prognostic factor (p = 0.025) for overall survival. In conclusion, autophagy may play a role in the tumorigenesis of SIACs, and LC3B and p62 could be used as prognostic biomarkers and potential therapeutic targets for SIACs.

Regulation and function of autophagy in pancreatic cancer

Oncogenic KRAS mutation-driven pancreatic ductal adenocarcinoma is currently the fourth-leading cause of cancer-related deaths in the United States. Macroautophagy (hereafter "autophagy") is one of the lysosome-dependent degradation systems that can remove abnormal proteins, damaged organelles, or invading pathogens by activating dynamic membrane structures (e.g., phagophores, autophagosomes, and autolysosomes). Impaired autophagy (including excessive activation and defects) is a pathological feature of human diseases, including pancreatic cancer. However, dysfunctional autophagy has many types and plays a complex role in pancreatic tumor biology, depending on various factors, such as tumor stage, microenvironment, immunometabolic state, and death signals. As a modulator connecting various cellular events, pharmacological targeting of nonselective autophagy may lead to both good and bad therapeutic effects. In contrast, targeting selective autophagy could reduce potential side effects of the drugs used. In this review, we describe the advances and challenges of autophagy in the development and therapy of pancreatic cancer.Abbreviations: AMPK: AMP-activated protein kinase; CQ: chloroquine; csc: cancer stem cells; DAMP: danger/damage-associated molecular pattern; EMT: epithelial-mesenchymal transition; lncRNA: long noncoding RNA; MIR: microRNA; PanIN: pancreatic intraepithelial neoplasia; PDAC: pancreatic ductal adenocarcinoma; PtdIns3K: phosphatidylinositol 3-kinase; SNARE: soluble NSF attachment protein receptor; UPS: ubiquitin-proteasome system.

AMBRA1 promotes TGF-β signaling via non-proteolytic polyubiquitylation of Smad4

Transforming growth factor-β (TGF-β) is pro-metastatic in advanced cancers and its biological activities are mainly mediated by the Smad family of proteins. Smad4 is the central signal transducer and transcription factor in the TGF-β pathway, yet the underlying mechanisms that govern transcriptional activities of Smad4 are not fully understood. Here, we show that AMBRA1, a member of the DDB1 and CUL4-associated factor (DCAF) family of proteins, serves as the substrate receptor for Smad4 in the CUL4-RING (CRL4) ubiquitin ligase complex. The CRL4-AMBRA1 ubiquitin ligase mediates non-proteolytic polyubiquitylation of Smad4 to enhance its transcriptional functions. Consequently, AMBRA1 potentiated TGF-β signaling and critically promoted TGF-β-induced epithelial-to-mesenchymal transition, migration, and invasion of breast cancer cells. Mouse models of breast cancer demonstrated that AMBRA1 promotes metastasis. Collectively, these results show that CRL4-AMBRA1 facilitates TGF-β-driven metastasis by increasing Smad4 polyubiquitylation, suggesting AMBRA1 may serve as a new therapeutic target in metastatic breast cancer.

ATP and cancer immunosurveillance

While intracellular adenosine triphosphate (ATP) occupies a key position in the bioenergetic metabolism of all the cellular compartments that form the tumor microenvironment (TME), extracellular ATP operates as a potent signal transducer. The net effects of purinergic signaling on the biology of the TME depend not only on the specific receptors and cell types involved, but also on the activation status of cis- and trans-regulatory circuitries. As an additional layer of complexity, extracellular ATP is rapidly catabolized by ectonucleotidases, culminating in the accumulation of metabolites that mediate distinct biological effects. Here, we discuss the molecular and cellular mechanisms through which ATP and its degradation products influence cancer immunosurveillance, with a focus on therapeutically targetable circuitries.

Mitophagy in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC), one of the most aggressive solid malignancies, is characterized by the presence of oncogenic KRAS mutations, poor response to current therapies, prone to metastasis, and a low 5-year overall survival rate. Macroautophagy (herein referred to as autophagy) is a lysosome-dependent degradation system that forms a series of dynamic membrane structures to engulf, degrade, and recycle various cargoes, such as unused proteins, damaged organelles, and invading pathogens. Autophagy is usually upregulated in established cancers, but it plays a dual role in the regulation of the initiation and progression of PDAC. As a type of selective autophagy, mitophagy is a mitochondrial quality control mechanism that uses ubiquitin-dependent (e.g., the PINK1-PRKN pathway) and -independent (e.g., BNIP3L/NIX, FUNDC1, and BNIP3) pathways to regulate mitochondrial turnover and participate in the modulation of metabolism and cell death. Genetically engineered mouse models indicate that the loss of PINK1 or PRKN promotes, whereas the depletion of BNIP3L inhibits oncogenic KRAS-driven pancreatic tumorigenesis. Mitophagy also play a dual role in the regulation of the anticancer activity of certain cytotoxic agents (e.g., rocaglamide A, dichloroacetate, fisetin, and P. suffruticosa extracts) in PDAC cells or xenograft models. In this min-review, we summarize the latest advances in understanding the complex role of mitophagy in the occurrence and treatment of PDAC.

Sexual differences in mitochondrial and related proteins in rat cerebral microvessels: A proteomic approach

Sex differences in mitochondrial numbers and function are present in large cerebral arteries, but it is unclear whether these differences extend to the microcirculation. We performed an assessment of mitochondria-related proteins in cerebral microvessels (MVs) isolated from young, male and female, Sprague-Dawley rats. MVs composed of arterioles, capillaries, and venules were isolated from the cerebrum and used to perform a 3 versus 3 quantitative, multiplexed proteomics experiment utilizing tandem mass tags (TMT), coupled with liquid chromatography/mass spectrometry (LC/MS). MS data and bioinformatic analyses were performed using Proteome Discoverer version 2.2 and Ingenuity Pathway Analysis. We identified a total of 1969 proteins, of which 1871 were quantified by TMT labels. Sixty-four proteins were expressed significantly (p < 0.05) higher in female samples compared with male samples. Females expressed more mitochondrial proteins involved in energy production, mitochondrial membrane structure, anti-oxidant enzyme proteins, and those involved in fatty acid oxidation. Conversely, males had higher expression levels of mitochondria-destructive proteins. Our findings reveal, for the first time, the full extent of sexual dimorphism in the mitochondrial metabolic protein profiles of MVs, which may contribute to sex-dependent cerebrovascular and neurological pathologies.

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.

The Role of Autophagy in Pancreatic Cancer: From Bench to the Dark Bedside

Pancreatic cancer is one of the deadliest cancer types urgently requiring effective therapeutic strategies. Autophagy occurs in several compartments of pancreatic cancer tissue including cancer cells, cancer associated fibroblasts, and immune cells where it can be subjected to a multitude of stimulatory and inhibitory signals fine-tuning its activity. Therefore, the effects of autophagy on pancreatic carcinogenesis and progression differ in a stage and context dependent manner. In the initiation stage autophagy hinders development of preneoplastic lesions; in the progression stage however, autophagy promotes tumor growth. This double-edged action of autophagy makes it a hard therapeutic target. Indeed, autophagy inhibitors have not yet shown survival improvements in clinical trials, indicating a need for better evaluation of existing results and smarter targeting techniques. Clearly, the role of autophagy in pancreatic cancer is complex and many aspects have to be considered when moving from the bench to the bedside.

Proteostasis Dysregulation in Pancreatic Cancer

The most common form of pancreatic cancer, pancreatic ductal adenocarcinoma (PDAC), has a dismal 5-year survival rate of less than 5%. Radical surgical resection, in combination with adjuvant chemotherapy, provides the best option for long-term patient survival. However, only approximately 20% of patients are resectable at the time of diagnosis, due to locally advanced or metastatic disease. There is an urgent need for the identification of new, specific, and more sensitive biomarkers for diagnosis, prognosis, and prediction to improve the treatment options for pancreatic cancer patients. Dysregulation of proteostasis is linked to many pathophysiological conditions, including various types of cancer. In this review, we report on findings relating to the main cellular protein degradation systems, the ubiquitin-proteasome system (UPS) and autophagy, in pancreatic cancer. The expression of several components of the proteolytic network, including E3 ubiquitin-ligases and deubiquitinating enzymes, are dysregulated in PDAC, which accounts for approximately 90% of all pancreatic malignancies. In the future, a deeper understanding of the emerging role of proteostasis in pancreatic cancer has the potential to provide clinically relevant biomarkers and new strategies for combinatorial therapeutic options to better help treat the patients.

TGFB1-induced autophagy affects the pattern of pancreatic cancer progression in distinct ways depending on SMAD4 status

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and lethal malignancies. Given that macroautophagy/autophagy activation is prevalent in PDAC, the dual roles of autophagy could be involved in PDAC heterogeneity. In this work, we demonstrated that TGFB1 induced autophagic flux through SMAD4-dependent or SMAD4-independent pathways based on a distinct genetic context. In SMAD4-positive PDAC cells, TGFB1-induced autophagy promoted proliferation and inhibited migration by decreasing the nuclear translocation of SMAD4. Conversely, TGFB1-induced autophagy inhibited proliferation and promoted migration in SMAD4-negative cells through the regulation of MAPK/ERK activation. TGFB1 expression also positively correlated with LC3B expression in PDAC specimens. A high level of LC3B was associated with unfavorable overall survival (OS) and disease-free survival (DFS) in SMAD4-negative PDAC patients, although LC3B could not predict OS and DFS for the 110 PDAC patients. Thus, TGFB1-induced autophagy contributed to the different patterns of PDAC progression. This knowledge can aid in improving our understanding of the molecular classification of PDAC and might guide the development of therapeutic strategies for PDAC, especially for SMAD4-negative PDAC.Abbreviations: CDH1: cadherin 1; CDH2: cadherin 2; CI: combination index; CQ: chloroquine; DFS: disease-free survival; EMT: epithelial-to-mesenchymal transition; ERK: extracellular signal-regulated protein kinase; GFP: green fluorescent protein; IHC: immunohistochemistry; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MAPK: mitogen-activated protein kinase; OS: overall survival; PBS: phosphate-buffered saline; PDAC: pancreatic ductal adenocarcinoma; RAP: rapamycin; RFP: red fluorescent protein; RT: room temperature; shRNA: short-hairpin RNA; SQSTM1: sequestosome 1; TCGA: The Cancer Genome Atlas; TEM: transmission electron microscopy; TGFB1: transforming growth factor beta 1; TMA: tissue microarray.

Autophagy and disease: unanswered questions

Autophagy is a process in which intracellular components and dysfunctional organelles are delivered to the lysosome for degradation and recycling. Autophagy has various connections to a large number of human diseases, as its functions are essential for cell survival, bioenergetic homeostasis, organism development, and cell death regulation. In the past two decades, substantial effort has been made to identify the roles of autophagy in tumor suppression and promotion, neurodegenerative disorders, and other pathophysiologies. This review summarizes the current advances and discusses the unanswered questions in understanding the involvement of autophagy in pathogenic mechanisms of disease, primarily focusing on cancer and neurodegenerative diseases.

Effects of neoadjuvant FOLFIRINOX and gemcitabine-based chemotherapy on cancer cell survival and death in patients with pancreatic ductal adenocarcinoma

Background: The progression and response to systemic treatment of cancer is substantially dependent on the balance between cancer cell death (apoptosis and necroptosis) and cancer cell survival (autophagy). Although well characterized in experimental systems, the status of cancer cell survival and cell death in human pancreatic ductal adenocarcinoma (PDAC), especially in response to chemotherapy and different types of chemotherapy is poorly described.

Results: The median (95% confidence interval) survival was 31.6 (24.5–44.5) months after FOLFIRINOX versus 15.8 (2.0–20.5) months after gemcitabine-based therapy (p = 0.039). PDAC tissue autophagy was reduced compared to normal pancreata based on reduced BECLIN-1 expression and LC3-Lamp-2 colocalization, whilst necroptosis (RIP-1) was increased. Neoadjuvant therapy was associated with further reduced autophagy based on p62/SQSTM-1 accumulation, and increased necroptosis (RIP3 and pMLKL) and apoptosis (BAX, cleaved CASPASE-9 and CASPASE-3) markers, increased nuclear p65 (NF-κB) and extracellular HMGB1 expression, with greater CD8⁺ lymphocyte infiltration. Survival was associated with reduced autophagy and increased apoptosis. Necroptosis (RIP-3, pMLKL) and apoptosis (BAX and cleaved CASPASE-9) markers were higher after FOLFIRINOX than gemcitabine-based treatment.

Patients and methods: Cancer cell autophagy, apoptosis, and necroptosis marker expression was compared in pancreatic tissue samples from 51 subjects, comprising four groups: (1) surgical resection for PDAC after FOLFIRINOX (n = 11), or (2) after gemcitabine-based (n = 14) neoadjuvant therapy, (3) patients undergoing PDAC resection without prior chemotherapy (n = 13), and (4) normal pancreata from 13 organ donors. Marker expression was undertaken using semi-automated immunofluorescence-FACS-like analysis, defining PDAC cells by CK-7⁺ expression.

Mitophagy in Cancer: A Tale of Adaptation

：In the past years, we have learnt that tumors co-evolve with their microenvironment, and that the active interaction between cancer cells and stromal cells plays a pivotal role in cancer initiation, progression and treatment response. Among the players involved, the pathways regulating mitochondrial functions have been shown to be crucial for both cancer and stromal cells. This is perhaps not surprising, considering that mitochondria in both cancerous and non-cancerous cells are decisive for vital metabolic and bioenergetic functions and to elicit cell death. The central part played by mitochondria also implies the existence of stringent mitochondrial quality control mechanisms, where a specialized autophagy pathway (mitophagy) ensures the selective removal of damaged or dysfunctional mitochondria. Although the molecular underpinnings of mitophagy regulation in mammalian cells remain incomplete, it is becoming clear that mitophagy pathways are intricately linked to the metabolic rewiring of cancer cells to support the high bioenergetic demand of the tumor. In this review, after a brief introduction of the main mitophagy regulators operating in mammalian cells, we discuss emerging cell autonomous roles of mitochondria quality control in cancer onset and progression. We also discuss the relevance of mitophagy in the cellular crosstalk with the tumor microenvironment and in anti-cancer therapy responses.

β-Catenin expression is associated with cell invasiveness in pancreatic cancer

BACKGROUND/AIMS

This study was tried to determine the role of β-catenin in invasion in pancreatic cancer.

METHODS

We analyzed cancer invasiveness according to β-catenin expression in pancreatic cancer cell line. We also investigated the change in cancer invasiveness when β-catenin expression was changed. To enhance β-catenin activity, we treated low β-catenin cancer cell line, PANC1, with Wnt-3a conditioned media and transected β-catenin. We also treated high β-catenin expressing cell line, BxPC3, with XAV939, β-catenin inhibitor and siRNA for β-catenin to inhibit β-catenin expression.

RESULTS

The high β-catenin expressing cancer cell line, BxPC3 showed higher invasiveness, and low β-catenin expressing cell lines, PANC1and MIA-PaCa-2, were less invasive. By adding the Wnt-3a conditioned media or performing transfection with β-catenin in PANC1, cell invasiveness was increased (p < 0.05 and p < 0.01, respectively). On inhibition of β-catenin by XAV939 and siRNA in BxPC3 cell line, invasiveness was significantly decreased (p < 0.01). It was not correlated with the expression of cluster of differentiation 44 (CD44) or CD44 variant 6 (CD44v6), the invasion related protein. On analysis of association with metastasis in human tissue, Wnt-3a expression was statistically correlated with the development of metastasis (p = 0.029).

CONCLUSION

Based on our data, β-catenin may be involved in cancer invasion in pancreatic cancer, and it is not associated with CD44, the invasion related protein.

Prognostic role of beclin-1 in locally advanced non-small cell lung cancer in patients receiving docetaxel-platinum induction chemotherapy

BACKGROUND/AIMS

The outcome of local treatment for advanced non-small cell lung cancer (NSCLC) remains poor, with therapies such as induction chemotherapy (IC) yielding conflicting results. This study aimed to assess the clinicopathologic and prognostic significance of the excision repair cross-complementation group 1 (ERCC1), beclin-1, and glucose-regulated protein of molecular mass 78 (GRP78) in patients with locally advanced NSCLC receiving docetaxel-platinum IC, along with efficacy and safety.

METHODS

This is a retrospective observational cohort study. We reviewed medical records of 31 NSCLC patients receiving docetaxel-platinum IC, and conducted immunohistochemical staining of ERCC1, beclin-1, and GRP78.

RESULTS

Response rate was 67.8% with 10.7 months of median relapse-free survival (RFS) and 23.1 months of median overall survival (OS), and no treatment-related death was reported. High expression of ERCC1, beclin-1, and GRP78 was identified in 67.7%, 87.1%, and 67.7%, respectively. Expression of ERCC1 and GRP78 did not reveal statistical significance in survival, whereas high beclin-1 expression revealed longer OS (7.6 months vs. 23.2 months; log-rank p = 0.024). In multivariate analysis, histologic differentiation (hazard ratio [HR], 3.48; p < 0.001), stage (HR, 8.5; p = 0.024), and adjuvant treatment (HR, 16.1; p = 0.001) were related to RFS, and in OS, stage (HR, 5.4; p = 0.037), adjuvant treatment (HR, 8.6; p = 0.004), and beclin-1 expression (HR, 8.2; p = 0.011) were identified as significant prognostic factors.

CONCLUSION

Our findings suggest that high beclin-1 expression predicts longer survival in locally advanced NSCLC and docetaxel-platinum IC is a treatment option that deserves consideration.

The role of metabolic adaptation to nutrient stress in pancreatic cancer

Pancreatic cancer is the fourth most common cause of cancer-related mortality, with a dismal prognosis that has changed little over the past few decades. Despite extensive efforts in understanding the oncogenetics of this pathology, pancreatic cancer remained largely elusive. One of the main characteristics of pancreatic cancer is the reduced level of oxygen and nutrient perfusion, caused by the new matrix formation, through the activation of stromal cells (desmoplasia). This stromal reaction leads to metabolic adaptations in surviving tumor cells in order to cope with these challenging conditions. The oncogenic signaling driven by KRAS mutation is necessary to fuel pancreatic tumors by activating key metabolic processes, including enhanced glycolysis and glutamine consumption. Here we review our current understanding of the pancreatic cancer metabolism as well as discuss recent work pointing to the importance of various metabolic strategies as well as autophagy and macropinocytosis as critical nutrient supply pathways. The elucidation of these metabolic networks may highlight new opportunities to further develop novel therapeutic strategies.

Prognostic and clinicopathological value of Beclin-1 expression in hepatocellular carcinoma: a meta-analysis

Background

The abnormal expression of Beclin-1 has recently been investigated in a variety of tumors. However, previous studies have obtained contradicting results regarding the clinical and prognostic value of Beclin-1 in hepatocellular carcinoma (HCC). We performed a meta-analysis to clarify the prognostic value of Beclin-1 and its correlations with clinical pathological parameters in HCC.

Methods

Relevant studies were systematically retrieved from PubMed, EMBASE, China National Knowledge Infrastructure (CNKI), Wan Fang and Chinese VIP databases. We used the Newcastle-Ottawa scale (NOS) to estimate the quality of the involved studies.

Results

Ten eligible studies with 1086 HCC patients were included in this study. Our results showed that decreased Beclin-1 expression in HCC related to histological grade [poor-undifferentiated vs. well-moderate: odds ratio (OR) = 2.34, 95% confidence interval (CI) = 1.65–3.32, P < 0.00001]. The pooled hazard ratio (HR) (HR = 1.43, 95% CI = 1.17–1.75, P = 0.0004) indicated that decreased Beclin-1 expression correlated with poor overall survival (OS).

Conclusions

This meta-analysis indicated that decreased Beclin-1 expression might relate to poor differentiation and unfavorable outcome in HCC.

Electronic supplementary material

The online version of this article (10.1186/s12957-018-1465-8) contains supplementary material, which is available to authorized users.

Knockdown of Beclin-1 impairs epithelial-mesenchymal transition of colon cancer cells

Activation of autophagy significantly affects cancer cell behaviors, such as proliferation, differentiation, and invasiveness. Epithelial-to-mesenchymal transition (EMT) as an initial step of malignant transformation of cancer cells was linked to the activation of autophagy, but the detailed molecular mechanisms are still unknown. The present study investigates the effects of Beclin-1, a key molecule involved in activation of autophagy, on EMT of colon cancer cells. The normal colon epithelia cell line of CCD-18Co and six colon cancer cell lines with different expression levels of Beclin-1 were used in this study. The activation of autophagy and EMT markers of cancer cells were monitored by Western blotting and quantitative real-time PCR assay in the presence or absence of rapamycin (autophagy activator) and 3-MA (autophagy inhibitor). The expression of Beclin-1 in selected cell lines was modulated using small interfering RNA, and consequentially EMT markers, and cancer cell behaviors including migration and invasion, were also explored. Activation or inhibition of autophagy in colon cancer cells had positive or negative impacts on the expression of EMT markers and malignant behaviors such as cell migration and invasion. Knockdown of beclin-1 by siRNA apparently inhibited the activation of autophagy induced by rapamycin, consequentially resulted in suppression of EMT and attenuation of invasiveness of colon cancer cells. The results in this study demonstrated an association between activation of autophagy and EMT in colon cancer cells. The results showed suppression of Beclin-1 expression significantly reduced EMT and invasive behaviors in colon cancer cells.

An autophagy-related gene expression signature for survival prediction in multiple cohorts of hepatocellular carcinoma patients

Prognostic signatures have been proposed as clinical tools to estimate prognosis in hepatocellular carcinoma (HCC), which is the second most common contributor to cancer-related death at present globally. Autophagy-related genes play a dynamic and fundamental role in HCC, but knowledge of their utility as prognostic markers is limited. Here, we facilitated univariate and multivariate Cox proportional hazards regression analyses to reveal that 3 autophagy-related genes (BIRC5, FOXO1 and SQSTM1) were closely related to the survival of HCC. Then, we generated a prognosis index (PI) for predicting overall survival (OS) based on the three genes, which was an independent prognostic indicator for the OS of HCC (HR = 1.930, 95% CI: 1.200-3.104, P = 0.007). The PI showed moderate performance for predicting the survival of HCC patients and its efficacy was validated by data from three microarrays (GSE10143, GSE10186 and GSE17856). Furthermore, we deeply mined the integrated large-scale datasets from public microarrays and immunohistochemistry to validate the overexpression of BIRC5 and SQSTM1 while down-regulated FOXO1 expression in HCC. Bioinformatic analysis offered the hypothesis that proliferative signals in high-risk HCC patients were disturbing and thereby facilitated inferior clinical outcomes. Collectively, the prognostic signature we proposed is a promising biomarker for monitoring outcome of HCC. Nevertheless, prospective experimental studies are needed to validate the clinical utility.

Transcriptional variations in the wider peritumoral tissue environment of pancreatic cancer

Transcriptional profiling was performed on 452 RNA preparations isolated from various types of pancreatic tissue from tumour patients and healthy donors, with a particular focus on peritumoral samples. Pancreatic ductal adenocarcinomas (PDAC) and cystic tumours were most different in these non-tumorous tissues surrounding them, whereas the actual tumours exhibited rather similar transcript patterns. The environment of cystic tumours was transcriptionally nearly identical to normal pancreas tissue. In contrast, the tissue around PDAC behaved a lot like the tumour, indicating some kind of field defect, while showing far less molecular resemblance to both chronic pancreatitis and healthy tissue. This suggests that the major pathogenic difference between cystic and ductal tumours may be due to their cellular environment rather than the few variations between the tumours. Lack of correlation between DNA methylation and transcript levels makes it unlikely that the observed field defect in the peritumoral tissue of PDAC is controlled to a large extent by such epigenetic regulation. Functionally, a strikingly large number of autophagy-related transcripts was changed in both PDAC and its peritumoral tissue, but not in other pancreatic tumours. A transcription signature of 15 autophagy-related genes was established that permits a prognosis of survival with high accuracy and indicates the role of autophagy in tumour biology.

Autophagy Inhibition in Pancreatic Adenocarcinoma

Although some progress has been made in recent years with the development of more effective chemotherapy regimens, new treatment approaches are needed to improve outcomes for patients with pancreatic adenocarcinoma. The cellular process of autophagy, a cell survival mechanism that allows cancer cells to survive the hazardous conditions of the tumor microenvironment and treatment, has emerged as a viable target in pancreatic cancer. We review the mechanism of autophagy, its role in pancreatic carcinogenesis, the preclinical and clinical evidence supporting targeting autophagy in patients with pancreatic adenocarcinoma, and areas of future investigation that hold promise for improving this treatment approach.

The Clinical Influence of Autophagy-Associated Proteins on Human Lung Cancer

Exploitation of autophagy might potentially improve therapeutic strategy. Here, we analyzed the protein expression of autophagy-associated genes including LC3A, LC3B, Beclin-1, p62, and Atg5 in 88–131 primary lung tumors by immunohistochemistry (IHC) on tissue-microarrays (TMAs). Additionally, the DNA methylation pattern of LC3A was investigated by bisulfite sequencing (BS) and methylation-specific-PCR (MSP). It turned out that the higher expression of LC3A protein was associated with adenocarcinoma compared to squamous cell carcinoma of lung (p = 0.008), positive staining of LC3B was significantly related to tumor grade (p = 0.006), and the protein expression of Beclin-1 was significantly correlated to pN stage (p = 0.041). The expression of p62 and Atg5 was however not significantly associated with any clinicopathological parameters. Downregulation of LC3A was related to DNA methylation in lung cancer cell lines, while in primary lung tumor samples, protein expression of LC3A was not significantly correlated with DNA methylation, and the methylation status of LC3A was not related to clinicopathological features. Taken together, our results suggest that autophagy-associated proteins such as LC3A, LC3B, and Beclin-1 might be potential biomarkers for subclassification, differentiation, and local metastasis in primary lung tumor, and epigenetic mechanism is partially responsible for gene silencing of LC3A in lung cancer cell lines.

New Insights Into Beclin-1: Evolution and Pan-Malignancy Inhibitor Activity

Autophagy is a functionally conserved self-degradation process that facilitates the survival of eukaryotic life via the management of cellular bioenergetics and maintenance of the fidelity of genomic DNA. The first known autophagy inducer was Beclin-1. Beclin-1 is expressed in multicellular eukaryotes ranging throughout plants to animals, comprising a nonmonophyllic group, as shown in this report via aggressive BLAST searches. In humans, Beclin-1 is a haploinsuffient tumor suppressor as biallelic deletions have not been observed in patient tumors clinically. Therefore, Beclin-1 fails the Knudson hypothesis, implicating expression of at least one Beclin-1 allele is essential for cancer cell survival. However, Beclin-1 is frequently monoallelically deleted in advanced human cancers and the expression of two Beclin-1 allelles is associated with greater anticancer effects. Overall, experimental evidence suggests that Beclin-1 inhibits tumor formation, angiogenesis, and metastasis alone and in cooperation with the tumor suppressive molecules UVRAG, Bif-1, Ambra1, and MDA-7/IL-24 via diverse mechanisms of action. Conversely, Beclin-1 is upregulated in cancer stem cells (CSCs), portending a role in cancer recurrence, and highlighting this molecule as an intriguing molecular target for the treatment of CSCs. Many aspects of Beclin-1's biological effects remain to be studied. The consequences of these BLAST searches on the molecular evolution of Beclin-1, and the eukaryotic branches of the tree of life, are discussed here in greater detail with future inquiry focused upon protist taxa. Also in this review, the effects of Beclin-1 on tumor suppression and cancer malignancy are discussed. Beclin-1 holds significant promise for the development of novel targeted cancer therapeutics and is anticipated to lead to a many advances in our understanding of eukaryotic evolution, multicellularity, and even the treatment of CSCs in the coming decades.

Beclin-1 knockdown decreases proliferation, invasion and migration of Ewing sarcoma SK-ES-1 cells via inhibition of MMP-9

Although Beclin-1, a well-known key regulator of autophagy, has been demonstrated to serve a function in a number of disorders, including cancer, aging and degenerative diseases, its biological function in Ewing sarcoma (ES) remains unresolved. The objective of the present study was to determine the in vitro effect of Beclin-1 knockdown on the growth and malignant phenotype of ES SK-ES-1 cells, which have increased endogenous expression of Beclin-1 compared with RD-ES cells, and to investigate the underlying molecular mechanism. Cell proliferation, invasion and migration were investigated using CCK-8, Boyden chamber Transwell, and wound healing assays, respectively. Western blot analysis was used to detect expression levels of matrix metalloproteinase (MMP)-2 and MMP-9, which are associated with the malignant phenotype. Beclin-1 knockdown significantly inhibited proliferation, invasion and migration of SK-ES-1 cells. Western blot analysis revealed that Beclin-1 knockdown caused a significant reduction in the expression of MMP-9; no marked changes in MMP-2 expression were observed in the si-Beclin-1 group compared with the control group. The results of the present study suggest that Beclin-1 serves a function in proliferation, tumor progression and inhibition of autophagy in ES, and demonstrates it's potential as a target to increase the efficacy of anticancer agents.

Clinical Applications of Autophagy Proteins in Cancer: From Potential Targets to Biomarkers

Autophagy, a lysosome-mediated intracellular degradation and recycling pathway, plays multiple context-dependent roles in tumorigenesis and treatment resistance. Encouraging results from various preclinical studies have led to the initiation of numerous clinical trials with the intention of targeting autophagy in various cancers. Accumulating knowledge of the particular mechanisms and players involved in different steps of autophagy regulation led to the ongoing discovery of small molecule inhibitors designed to disrupt this highly orchestrated process. However, the development of validated autophagy-related biomarkers, essential for rational selection of patients entering clinical trials involving autophagy inhibitors, is lagging behind. One possible source of biomarkers for this purpose is the autophagy machinery itself. In this review, we address the recent trends, challenges and advances in the assessment of the biomarker potential of clinically relevant autophagy proteins in human cancers.

Autophagy-related gene expression is an independent prognostic indicator of glioma

In this study, we identified 74 differentially expressed autophagy-related genes in glioma patients. Analysis using a Cox proportional hazard regression model showed that MAPK8IP1 and SH3GLB1, two autophagy-related genes, were associated with the prognostic signature for glioma. Glioma patients from the CGGA batches 1 and 2, GSE4412 and TCGA datasets could be divided into high- and low-risk groups with different survival times based on levels of MAPK8IP1 and SH3GLB1 expression. The autophagy-related signature was an independent predictor of survival outcomes in glioma patients. MAPK8IP1 overexpression and SH3GLB1 knockdown inhibited glioma cell proliferation, migration and invasion, and improved Temozolomide sensitivity. These findings suggest autophagy-related genes like MAPK8IP1 and SH3GLB1 could be potential therapeutic targets in glioma.

The role of autophagy in hepatocellular carcinoma: friend or foe

Autophagy is an evolutionarily conserved lysosome-dependent catabolic process which degrades cell’s components in order to recycle substrates to exert optimally and adapt to tough circumstances. It is a critical cellular homeostatic mechanism with stress resistance, immunity, antiaging, and pro-tumor or anti-tumor effects. Among these, the role of autophagy in cancer is the most eye-catching that is not immutable but dynamic and highly complex. Basal autophagy acts as a tumor suppressor by maintaining genomic stability in normal cells. However, once a tumor is established, unbalanced autophagy will contribute to carcinoma cell survival under tumor microenvironment and in turn promote tumor growth and development. The dynamic role of autophagy can also apply on hepatocellular carcinoma (HCC). HCC is a highly malignant cancer with high morbidity and poor survival rate. Decline or overexpression of autophagic essential genes such as ATG7, ATG5 or Beclin 1 plays a key role in the occurrence and development of HCC but the exact mechanisms are still highly controversial. Signaling pathways or molecules involving in autophagy, for example PI3K/AKT/mTOR pathway, ERK/MAPK pathway, PERK pathway, p53, LncRNA PTENP1 (Long non-coding RNA PTENP1), microRNA-375 and so on, occupy an important position in the complex role of autophagy in HCC. Here, we discuss the dynamic role, the signaling pathways and the potential prognostic and therapy value of autophagy in HCC.

Prognostic significance of autophagy-related proteins expression in resected human gastric adenocarcinoma

Gastric adenocarcinoma (GC) is one of the most common malignancies in the world and one of the most frequent causes of cancer-related death. Autophagy is a highly regulated catabolic pathway responsible for the degradation of long-lived proteins and damaged intracellular organelles. However, the mechanism and guiding significance of autophagy in the development and progression of GC have remained to be elucidated. This study aimed to explore the clinicopathological significances and prognostic values of autophagy-related proteins AMBRA1 and Beclin-1 in GC. Quantum dots based immunofluorescence histochemistry (QDs-IHC) was performed to observe the expression of AMBRA1 and Beclin-1 proteins in the tissue microarrays including 163 specimens of GC and 20 noncancerous gastric tissues. Simultaneously, AMBRA1 and Beclin-1 proteins were detected by Western blotting in the 10 fresh GC and corresponding normal gastric tissues. The results showed that the expression levels of both AMBRA1 and Beclin-1 proteins were higher in GC tissues than in noncancerous gastric tissues by QDs-IHC and Western blotting (P<0.05). High AMBRA1 expression was detected in 90 of 163 (55.2%) GCs and high Beclin-1 expression was detected in 83 of 163 (50.9%) GCs. High AMBRA1 expression was closely related to depth of invasion, and lymph nodes metastasis (P<0.05). High expression of Beclin-1 protein was correlated with tumor grade (P<0.05). Positive correlation was observed between AMBRA1 and Beclin-1. Survival analysis indicated the high expression of AMBRA1 and Beclin- 1 was an independent factor in predicting poor overall survival (OS) of GC patients. These findings suggest the high expression of AMBRA1 and Beclin-1 proteins is significantly correlated with GC progression. High AMBRA1 and Beclin-1 expression heralds worse outcome of GC patients, suggesting a novel candidate prognostic marker and a therapeutic target for GC.

Bif-1 promotes tumor cell migration and metastasis via Cdc42 expression and activity

Tumor metastasis is the process by which tumor cells disseminate from tumors and enter nearby and distant microenvironments for new colonization. Bif-1 (BAX-interacting factor 1), which has a BAR domain and an SH3 domain, has been reported to be involved in cell growth, apoptosis and autophagy. However, the influence of Bif-1 on metastasis has been less studied. To understand the role of Bif-1 in metastasis, we studied the expression levels of Bif-1 in human HCC specimens using immunohistochemistry, a tissue microarray and quantitative PCR. The function of Bif-1 was assessed in migration and translocation assays and the pulmonary metastatic animal model. The relationship between Bif-1 and the Rho family was determined using immunoblot analyses and chromatin immunoprecipitation. The results showed that the expression of Bif-1 was higher in hepatocellular carcinoma (HCC) than matched adjacent non-tumor liver tissues. Increased Bif-1 expression was associated with tumor size and the intercellular spread and metastasis of HCC. Analysis of the relationship between Bif-1 expression and patients' clinical characteristics revealed that patients with higher levels of Bif-1 had shorter disease-free and overall survival rates. Knockdown of Bif-1 with RNAi suppressed the migration of HCC cells and pulmonary metastasis and decreased the expression of Cdc42, a member of the Rho family. Bif-1 localized to the cytosol and nucleus and interacted with the promoter transcription region of Cdc42, which may regulate Cdc42 expression. Our results demonstrate a novel role of Bif-1 in HCC, in which Bif-1 promotes cell metastasis by regulating Cdc42 expression and activity.

Prognostic relevance of autophagy-related markers LC3, p62/sequestosome 1, Beclin-1 and ULK1 in colorectal cancer patients with respect to KRAS mutational status

Background

Autophagy is a cellular pathway that regulates transportation of cytoplasmic macromolecules and organelles to lysosomes for degradation. Autophagy is involved in both tumorigenesis and tumour suppression. Here we investigated the potential prognostic value of the autophagy-related proteins Beclin-1, p62, LC3 and uncoordinated (UNC) 51-like kinase 1 (ULK1) in a cohort of colorectal cancer (CRC) specimens.

Methods

In this study, we analysed the immunoexpression of the autophagy-related proteins p62, LC3, Beclin-1 and ULK1 in 127 CRC patients with known KRAS mutational status and detailed clinical follow-up.

Results

Survival analysis of p62 staining showed a significant correlation of cytoplasmic (not nuclear) p62 expression with a favourable tumour-specific overall survival (OS). The prognostic power of cytoplasmic p62 was found in the KRAS-mutated subgroup but was lost in the KRAS wildtype subgroup. Survival analysis of Beclin-1 staining did not show an association with OS in the complete cohort. LC3 overexpression demonstrated a slight, though not significant, association with decreased OS. Upon stratifying cases by KRAS mutational status, nuclear (not cytoplasmic) Beclin-1 staining was associated with a significantly decreased OS in the KRAS-mutated subgroup but not in the KRAS wildtype CRCs. In addition, LC3 overexpression was significantly associated with decreased OS in the KRAS-mutated CRC subgroup. ULK1 expression was not correlated to survival.

Conclusions

Immunohistochemical analyses of LC3, p62 and Beclin-1 may constitute promising novel prognostic markers in CRC, especially in KRAS-mutated CRCs. This strategy might help in identifying high-risk patients who would benefit from autophagy-related anticancer drugs.

Electronic supplementary material

The online version of this article (doi:10.1186/s12957-016-0946-x) contains supplementary material, which is available to authorized users.

Long Noncoding RNA MALAT1 Promotes Aggressive Pancreatic Cancer Proliferation and Metastasis via the Stimulation of Autophagy

Recently, pancreatic ductal adenocarcinoma (PDAC) has emerged as one of the most aggressive malignant tumors with the worst prognosis. Previous studies have demonstrated that long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is increased in pancreatic cancer and is identified as a diagnostic biomarker. Nonetheless, the molecular mechanism of elevated MALAT1 levels and tumor aggressiveness remains unknown. In this study, MALAT1 was found to be highly expressed in PDAC tissues, and elevated expression was associated with poorer prognoses. In addition, MALAT1 was positively linearly correlated with the expression of LC3B mRNA. Furthermore, several molecules involved in cellular autophagic flux were modulated following the downregulation of MALAT1, including LC3, P62, and LAMP-2. Mechanistically, we found that MALAT1 interacted with RNA binding protein HuR, and silencing of MALAT1 greatly enhanced the posttranscriptional regulation of TIA-1 and had further effects on inhibiting autophagy. MALAT1 was speculated to regulate tumorigenesis via HuR-TIA-1-mediated autophagic activation. Hence, we investigated the biological properties of MALAT1 in terms of tumor proliferation and metastasis by promoting autophagy in vitro In brief, these data demonstrate that MALAT1 could facilitate the advanced progression of tumors in vivo Our study highlights the new roles of MALAT1 on protumorigenic functioning and anticancer therapy via activating autophagy in pancreatic cancer. Mol Cancer Ther; 15(9); 2232-43. ©2016 AACR.

Ambra1 in autophagy and apoptosis: Implications for cell survival and chemotherapy resistance

Increasing studies suggest that autophagy has a protective role in cancer treatment and may even be involved in chemotherapy resistance. Nevertheless, the mechanism of autophagy in cancer treatment and drug resistance has not yet been established. There is a complex association between autophagy and apoptosis. Accordingly, these two processes can mutually regulate and transform to determine the fate of a cell, depending on the context. Activating molecule in Beclin 1-regulated autophagy protein 1 (Ambra1) is an important factor at the crossroad between autophagy and apoptosis. The expression level and intracellular distributions of Ambra1 may control the balance and conversion between autophagy and apoptosis, and modify the effectiveness of chemotherapy. Therefore, Ambra1 may provide a novel target for cancer treatment, particularly for overcoming anticancer drug resistance. The present review focuses on the role of Ambra1 in autophagy and apoptosis and assesses the implications for cell survival and chemotherapy resistance.

Role of autophagy-related protein expression in patients with rectal cancer treated with neoadjuvant chemoradiotherapy

Background

Autophagy, a cellular degradation process, has complex roles in tumourigenesis and resistance to cancer treatment in humans. The aim of this study was to explore the expression levels of autophagy-related proteins in patients with rectal cancer and evaluate their clinical role in the neoadjuvant chemoradiotherapy setting.

Methods

All specimens evaluated were obtained from 101 patients with colorectal cancer who had undergone neoadjuvant chemoradiotherapy and curative surgery. The primary outcomes measured were the expression levels of two autophagy-related proteins (microtubule-associated protein 1 light chain 3 beta (LC3β) and beclin-1) by immunohistochemistry and their association with clinicopathological parameters and patient survival.

Results

Among the 101 patients, the frequency of high expression of beclin-1 was 31.7 % (32/101) and that of LC3β was 46.5 % (47/101). A pathologic complete response was inversely associated with LC3β expression (P = 0.003) and alterations in the expression of autophagy-related proteins (P = 0.046). In the multivariate analysis, however, autophagy-related protein expression did not show prognostic significance for relapse-free survival or overall survival.

Conclusions

High expression of autophagy-related proteins shows a strong negative association with the efficacy of neoadjuvant chemoradiotherapy in patients with rectal cancer. Autophagy has clear implications as a therapeutic target with which to improve the efficacy of neoadjuvant chemoradiotherapy.

Mitophagy programs: mechanisms and physiological implications of mitochondrial targeting by autophagy

Mitochondria are an essential source of ATP for cellular function, but when damaged, mitochondria generate a plethora of stress signals, which lead to cellular dysfunction and eventually programmed cell death. Thus, a major component of maintaining cellular homeostasis is the recognition and removal of dysfunctional mitochondria through autophagy-mediated degradation, i.e., mitophagy. Mitophagy further constitutes a developmental program, and undergoes a high degree of crosstalk with apoptosis. Reduced mitochondrial quality control is linked to disease pathogenesis, suggesting the importance of process elucidation as a clinical target. Recent work has revealed multiple mitophagy programs that operate independently or undergo crosstalk, and require modulated autophagy receptor activities at outer membranes of mitochondria. Here, we review these mitophagy programs, focusing on pathway mechanisms which recognize and target mitochondria for sequestration by autophagosomes, as well as mechanisms controlling pathway activities. Furthermore, we provide an introduction to the currently available methods for detecting mitophagy.

Prognostic and Predictive Value of DAMPs and DAMP-Associated Processes in Cancer

It is now clear that human neoplasms form, progress, and respond to therapy in the context of an intimate crosstalk with the host immune system. In particular, accumulating evidence demonstrates that the efficacy of most, if not all, chemo- and radiotherapeutic agents commonly employed in the clinic critically depends on the (re)activation of tumor-targeting immune responses. One of the mechanisms whereby conventional chemotherapeutics, targeted anticancer agents, and radiotherapy can provoke a therapeutically relevant, adaptive immune response against malignant cells is commonly known as “immunogenic cell death.” Importantly, dying cancer cells are perceived as immunogenic only when they emit a set of immunostimulatory signals upon the activation of intracellular stress response pathways. The emission of these signals, which are generally referred to as “damage-associated molecular patterns” (DAMPs), may therefore predict whether patients will respond to chemotherapy or not, at least in some settings. Here, we review clinical data indicating that DAMPs and DAMP-associated stress responses might have prognostic or predictive value for cancer patients.

The association of statin use after cancer diagnosis with survival in pancreatic cancer patients: a SEER-medicare analysis

Background

Pancreatic cancer has poor prognosis and existing interventions provide a modest benefit. Statin has anti-cancer properties that might enhance survival in pancreatic cancer patients. We sought to determine whether statin treatment after cancer diagnosis is associated with longer survival in those with pancreatic ductal adenocarcinoma (PDAC).

Methods

We analyzed data on 7813 elderly patients with PDAC using the linked Surveillance, Epidemiology, and End Results (SEER) - Medicare claims files. Information on the type, intensity and duration of statin use after cancer diagnosis was extracted from Medicare Part D. We treated statin as a time-dependent variable in a Cox regression model to determine the association with overall survival adjusting for follow-up, age, sex, race, neighborhood income, stage, grade, tumor size, pancreatectomy, chemotherapy, radiation, obesity, dyslipidemia, diabetes, chronic pancreatitis and chronic obstructive pulmonary disease (COPD).

Results

Overall, statin use after cancer diagnosis was not significantly associated with survival when all PDAC patients were considered (HR = 0.94, 95%CI 0.89, 1.01). However, statin use after cancer diagnosis was associated with a 21% reduced hazard of death (Hazard ratio = 0.79, 95% confidence interval (CI) 0.67, 0.93) in those with grade I or II PDAC and to a similar extent in those who had undergone a pancreatectomy, in those with chronic pancreatitis and in those who had not been treated with statin prior to cancer diagnosis.

Conclusions

We found that statin treatment after cancer diagnosis is associated with enhanced survival in patients with low-grade, resectable PDAC.

Connecting autophagy: AMBRA1 and its network of regulation

During autophagy, a double-membraned vesicle called the autophagosome is responsible for the degradation of long-lived proteins and damaged/old organelles, thus contributing to the maintenance of cellular homeostasis. Physiological stimuli and stressors enhance autophagy in order to accomplish important processes such as cell differentiation or as a cytoprotective response. In line with this, numerous studies have demonstrated the relevance of proper autophagy regulation to health. Autophagy defects are associated with the insurgence of neurological/neurodegenerative diseases and cancer. Moreover, the autophagy pathway is often potentiated in cancer cells to increase cell survival. Increased knowledge of the molecular mechanisms underlying autophagy regulation and their interplay with other cellular pathways would provide advances in cancer treatment. In this context, post-translational modifications, protein-protein interactions, and regulative feedback loops offer promising insights. In this review, we focus on AMBRA1, a proautophagic protein that was recently demonstrated to participate in numerous crucial regulative mechanisms of the autophagy process.

Untangling knots between autophagic targets and candidate drugs, in cancer therapy

Autophagy is an evolutionarily conserved lysosomal mechanism implicated in a wide variety of pathological processes, such as cancer. Autophagy can be regulated by a limited number of autophagy-related genes (Atgs) such as oncogenic Bcl-2/Bcl-XL , mTORC1, Akt and PI3KCI, and tumour suppressive proteins PI3KCIII, Beclin-1, Bif-1, p53, DAPKs, PTEN and UVRAG, which play their crucial roles in regulating autophagy-related cancer. As autophagy has a dual role in cancer cells, with tumour-promoting and tumour-suppressing properties, it has become an attractive target for a series of emerging small molecule drugs. In this review, we reveal new discoveries of related small molecules or chemical compounds that can regulate autophagic pathways and lead to pro-death or pro-survival autophagy, in different types of cancer. We discuss the knots between autophagic targets and candidate drugs, in the hope of shedding new light on exploiting new anti-tumour small molecule drugs for future cancer therapy.

Autophagic LC3B overexpression correlates with malignant progression and predicts a poor prognosis in hepatocellular carcinoma

Autophagy is a process that involves lysosomal degradations of cellular organelles and closely related to tumor occurrence and progression. However, its importance in hepatocellular carcinoma (HCC) was still controversial. Therefore, this study is aimed to address the clinicopathologic effect of microtubule-associated protein 1 light chain 3B (LC3B) and Beclin-1, as autophagic markers, in HCC patients. Tissue microarray-based immunohistochemistry was used to examine the expression of LC3B and another autophagy key regulator (Beclin-1) in 156 operable HCC patients. Kaplan-Meier analysis, chi-square test, and Spearman's correlation analysis were used to analyze correlation of LC3B and Beclin-1 and their influence on clinical characteristics and prognosis. We found that the expression level of LC3B was significantly associated with vascular invasion (P = 0.008), lymph node metastasis (P < 0.001), and Beclin-1 expression level (P < 0.001). However, LC3B was not related to other clinicopathological features, including hepatitis B virus infection, liver cirrhosis, tumor number, tumor size, pathology grade, and tumor-node-metastasis (TNM) stage. Besides, correlation between the expression of Beclin-1 and clinicopathological features were not identified. Survival analysis showed that patients with high LC3B expression had a poorer 5-year overall survival (OS) rate than those with low LC3B expression (high vs. low: 79.5 % vs. 20.5 %, P = 0.026). And high LC3B expression tended to be related with shorter progression-free survival (PFS) (P = 0.074), whereas the expression level of Beclin-1 did not show statistically significant association with OS or PFS. Further multivariate analysis revealed that lymph node metastasis (P = 0.047) and LC3B expression level (P = 0.047) were independent factors to predict the prognosis of OS in all patients. Our study demonstrated that high expression of LC3B, correlated with vascular invasion and lymph node metastasis, might be a novel prognostic biomarker and would be a potential therapy target for HCC, especially in operable patients.

Human papillomavirus-stratified analysis of the prognostic role of miR-21 in oral cavity and oropharyngeal squamous cell carcinoma

Human papillomavirus (HPV) infection plays a significant role in the development and progression of head and neck squamous cell carcinoma (HNSCC). Expression of miR-21 has a prognostic role in a wide variety of cancers. The upregulation of miR-21 suppresses a number of target genes, including phosphatase tensin homologue (PTEN) and programmed cell death 4 (PDCD4). We investigated the association between the expression of miR-21 and the clinical features of HNSCC using stratified analysis based on HPV infection status. HPV status and miR-21 expression in HNSCC tissues from 167 patients were evaluated using in situ hybridization. The expression of PDCD4 and PTEN was examined by immunohistochemistry. The up-regulation of stromal miR-21 expression occurred in 40.6% of HPV-negative samples and 28.3% of the HPV-positive group. In HPV-stratified multivariate analysis, high miR-21 expression was associated with poor cancer-specific survival in HPV-negative tumors, but not in HPV-positive tumors. There was a significant association between miR-21 and cytoplasmic PDCD4 overexpression in HPV-negative HNSCCs. We suggest that stromal miR-21 expression is an independent prognostic factor in HPV-negative tumors and miR-21 may play different roles depending on HPV infection status.