Beclin 1 deficiency correlated with lymph node metastasis, predicts a distinct outcome in intrahepatic and extrahepatic cholangiocarcinoma. PLoS One. 2013;8:e80317. [PMID: 24303007 PMCID: PMC3841169 DOI: 10.1371/journal.pone.0080317]

Preclinical evidence for preventive and curative effects of resveratrol on xenograft cholangiocarcinogenesis

Cholangiocarcinoma (CCA), the malignant tumor of bile duct epithelial cells, is a relatively rare yet highly lethal cancer. In this work, we tested the ability of Resveratrol (RV) to prevent and cure CCA xenograft in nude mice and investigated molecular mechanisms underpinning such anticancer effect. Human CCA cells were xenografted in mice that were or not treated prior to or after to transplantation with RV. Tumor growth was monitored and analyzed for the markers of cell proliferation, apoptosis, and autophagy. TCGA was interrogated for the molecules possibly targeted by RV. RV could inhibit the growth of human CCA xenograft when administered after implantation and could reduce the growth or even impair the implantation of the tumors when administered prior the transplantation. RV inhibited CCA cell proliferation, induced apoptosis with autophagy, and strongly reduced the presence of CAFs and production of IL-6. Interrogation of CCA dataset in TCGA database revealed that the expression of IL-6 Receptor (IL-6R) inversely correlated with that of MAP-LC3 and BECLIN-1, and that low expression of IL-6R and of MIK67, two pathways downregulated by RV, associated with better survival of CCA patients. Our data demonstrate that RV elicits a strong preventive and curative anticancer effect in CCA by limiting the formation of CAFs and their release of IL-6, and this results in up-regulation of autophagy and apoptosis in the cancer cells. These findings support the clinical use of RV as a primary line of prevention in patients exposed at risk and as an adjuvant therapeutics in CCA patients.

COTE1 Facilitates Intrahepatic Cholangiocarcinoma Progression via Beclin1-Dependent Autophagy Inhibition

COTE1 was recently described as an oncogene in hepatocellular carcinoma and gastric cancer. However, the roles of COTE1 in intrahepatic cholangiocarcinoma (ICC) are little known. Our study is aimed at clarifying novel functions of COTE1 in ICC progression, including proliferation, invasion, and autophagy. By using quantitative real-time PCR, immunohistochemistry staining, and western blotting, we found that COTE1 expression was frequently upregulated in ICC tissues, compared to paracarcinoma tissues. High COTE1 expression was significantly correlated with aggressive clinical features and predicted poor prognosis of ICC patients. Functional experiments revealed that ectopic COTE1 expression promoted ICC cell proliferation, colony formation, cellular invasion, migration, and in vivo tumorigenicity; in contrast, COTE1 knockdown resulted in the opposite effects. At molecular mechanism in vitro and vivo, our study revealed that COTE1 overexpression suppressed autophagy via Beclin1 transcription inhibition; conversely, COTE1 silencing facilitated autophagy through promoting Beclin1 expression. Furthermore, the suppression of COTE1 knockdown on cellular growth and invasion was rescued/aggravated by Beclin1 inhibition/accumulation. Our data, for the first time, illustrate that COTE1 is an oncogene in ICC pathogenesis, and the ectopic COTE1 expression promotes ICC proliferation and invasion via Beclin1-dependent autophagy inhibition.

The role and implication of autophagy in cholangiocarcinoma

Cholangiocarcinoma (CCA) is a malignant tumor that originates from the biliary epithelial cells. It is characterized by a difficult diagnosis and limited treatment options. Autophagy is a cellular survival mechanism that maintains nutrient and energy homeostasis and eliminates intracellular pathogens. It is involved in various physiological and pathological processes, including the development of cancer. However, the role, mechanism, and potential therapeutic targets of autophagy in CCA have not been thoroughly studied. In this review, we introduce the classification, characteristics, process, and related regulatory genes of autophagy. We summarize the regulation of autophagy on the progression of CCA and collect the latest research progress on some autophagy modulators with clinical potential in CCA. In conclusion, combining autophagy modulators with immunotherapy, chemotherapy, and targeted therapy has great potential in the treatment of CCA. This combination may be a potential therapeutic target for CCA in the future.

Active Autophagy Is Associated with Favorable Outcome in Patients with Surgically Resected Cholangiocarcinoma

Data on the impact of autophagy in primary cholangiocarcinoma (CCA) remain scarce. Here, we therefore investigated the role of active autophagy and its impact on survival in CCA patients. All CCA patients who underwent surgical resection with curative intent between 08/2005 and 12/2021 at University Hospital Frankfurt were evaluated. Autophagic key proteins were studied by immunohistochemistry. iCCA processed for gene expression profiling of immune-exhaustion gene sets was used for an autophagy approach in silico. Active autophagy was present in 23.3% of the 172 CCA patients. Kaplan-Meier curves revealed median OS of 68.4 months (95% CI = 46.9-89.9 months) and 32.7 months (95% CI = 23.6-41.8 months) for active and non-active autophagy, respectively (p ≤ 0.001). In multivariate analysis, absence of active autophagy (HR = 2, 95% CI = 1.1-3.5, p = 0.015) was an independent risk factor for OS. Differential-expression profiling revealed significantly upregulated histone deacetylases (HDAC) mRNA in patients showing non-active autophagy. In line with this, pan-acetylated lysine was significantly more prominent in CCA patients with ongoing autophagy (p = 0.005). Our findings strengthen the role of active autophagy as a prognostically relevant marker and a potential therapeutic target.

Albendazole-induced autophagy blockade contributes to elevated apoptosis in cholangiocarcinoma cells through AMPK/mTOR activation

Albendazole (ABZ) is a broad-spectrum anti-parasitic drug that exhibits antitumor effects against several carcinomas. The effects of ABZ on cholangiocarcinoma (CCA) and its underlying mechanisms are still unclear. Our study aims to investigate the role of ABZ in inducing autophagy-mediated apoptosis of cholangiocarcinoma cells. The antitumor effects of ABZ were evaluated against CCA cells and HIBEC intrahepatic biliary epithelial cells. Furthermore, the apoptosis rates, and autophagy flux in RBE and FRH-0201 cells treated with ABZ were investigated. ABZ inhibited proliferation, induced cell death and apoptosis in CCA cells in vitro. In vivo, tumors from ABZ- treated BALB/c nude mice were significantly smaller than untreated mice. ABZ also induced the initiation of autophagy via AMPK/mTOR pathways, resulting in the formation of autophagosome. In addition, ABZ blocked autophagic flux by inhibiting the fusion of autophagosome-lysosome, which increased the apoptotic death of CCA cells. However, the apoptotic death of CCA cells induced by ABZ was reversed by 3-methyladenine (3-MA), an autophagosome formation inhibitor, but increased by chloroquine (CQ), an autophagosome-lysosome fusion inhibitor.Our work provides novel mechanisms for anti-tumor effects of ABZ on CCA, suggesting that ABZ may be used as a potent autophagy inhibitor in the treatment of CCA.

Role of autophagy in cholangiocarcinoma: Pathophysiology and implications for therapy

Cholangiocarcinoma (CCA) is a malignant tumour of the biliary system that originates from the neoplastic transformation of cholangiocytes. CCA is characterized by late diagnosis and poor outcome, with surgery considered as the last option for management. Autophagy is a physiological lysosomal degradation process, essential for cellular homeostasis and ubiquitous in all eukaryotic cells. Several studies have reported a potential involvement of autophagy in cancer, but it remains unclear whether activation of this process represents a survival mechanism of cancer cells. In the present review, we examine the autophagic process and summarize the current knowledge about the involvement of autophagy in the progression of cancer. The link between autophagy and chemoresistance and the use of autophagic markers in diagnosis are also considered in detail. Preliminary evidence shows that the combination of autophagy modulators (activators or inhibitors) with conventional chemotherapeutic agents offers a possible treatment option against signalling pathways that are hyperactivated or altered in CCA. In vitro evidence suggests that combination of chemotherapy agents, such as cisplatin, under activation or inhibition of autophagic processes, in two different CCA cell lines, may improve chemosensitivity and reduce cell survival, respectively. A deeper understanding of these pathways, in both cancer and non-cancer cells, could unveil possible therapeutic targets to treat CCA patients.

Role of autophagy-related protein in the prognosis of combined hepatocellular carcinoma and cholangiocarcinoma after surgical resection

Background

Autophagy-related proteins may predict postresection overall survival (OS) and disease-free survival (DFS) in patients with combined hepatocellular carcinoma and cholangiocarcinoma (cHCC-CC).

Methods

We prospectively investigated how these proteins affect clinical prognosis in 40 patients who underwent hepatectomy for cHCC-CC from 2011 to 2019 at a Taiwanese hospital. Levels of autophagy-related proteins, namely LC3, Beclin-1, and p62, were immunohistochemically assessed in patient tumor and non-tumor tissues.

Results

We noted that LC3 expression was significantly correlated with mild clinicopathological characteristics, including macrovascular invasion, lymph node metastasis, American Joint Committee on Cancer and Barcelona Clinic Liver Cancer stages, recurrence, and mortality. Ten patient showed tumor recurrence, and 15 patients died. Postresection 5-year OS and DFS rates were 43.7 and 57.4%, respectively. Cox regression analysis showed that high intratumoral LC3 expression was significantly associated with improved OS [hazard ratio (HR; 95% confidence interval (CI)): (1.68–26.9), p = 0.007], but multiple tumors and microvascular invasion was significantly correlated with poor OS [HR (95% CI): 0.03 (0.01–0.34), p = 0.004, and 0.07 (0.01–0.46), p = 0.006, respectively]. Furthermore, high LC3 expression and cirrhosis had improved DFS [HR (95% CI): 51.3 (2.85–922), p = 0.008, and 17.9 (1.05–306), p = 0.046, respectively]. The 5-year OS and DFS rates were respectively 61.2 and 74.6% in high LC3 expression patients and 0 and 0% in those with low LC3 expression.

Conclusion

High LC3 expression in tumors is significantly associated with mild clinicopathological characteristics and favorable clinical prognosis in patients with cHCC-CC after resection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08553-6.

c-FLIP regulates autophagy by interacting with Beclin-1 and influencing its stability

c-FLIP (cellular FLICE-like inhibitory protein) protein is mostly known as an apoptosis modulator. However, increasing data underline that c-FLIP plays multiple roles in cellular homoeostasis, influencing differently the same pathways depending on its expression level and isoform predominance. Few and controversial data are available regarding c-FLIP function in autophagy. Here we show that autophagic flux is less effective in c-FLIP−/− than in WT MEFs (mouse embryonic fibroblasts). Indeed, we show that the absence of c-FLIP compromises the expression levels of pivotal factors in the generation of autophagosomes. In line with the role of c-FLIP as a scaffold protein, we found that c-FLIP_L interacts with Beclin-1 (BECN1: coiled-coil, moesin-like BCL2-interacting protein), which is required for autophagosome nucleation. By a combination of bioinformatics tools and biochemistry assays, we demonstrate that c-FLIP_L interaction with Beclin-1 is important to prevent Beclin-1 ubiquitination and degradation through the proteasomal pathway. Taken together, our data describe a novel molecular mechanism through which c-FLIP_L positively regulates autophagy, by enhancing Beclin-1 protein stability.

Autophagy activity in cholangiocarcinoma is associated with anatomical localization of the tumor

The presence of autophagy has been indicated in cholangiocarcinoma (CC), which disease has poor prognosis and limited treatment options. Recently, CC has been classified by anatomical localization as intrahepatic (iCC), perihilar (pCC) and distal (dCC), showing different clinical and molecular characteristics. Thus, our aim was to compare autophagy activity in CC samples resected from different anatomical locations. Further, we investigated whether autophagy could be modulated in cell lines originated from iCC and extrahepatic CC (eCC) following the treatments with autophagy inhibitory and inducing agents. Tissue microarrays were prepared from 70 CC (28 iCC, 19 pCC and 23 dCC), 31 adjacent non-tumorous and 9 hepatocellular carcinoma (HCC) samples. Autophagy markers LC3, p62 and Beclin1 as well as proliferation marker Ki-67 were monitored by immunohistochemistry and were associated with patients' survival. Modulation of autophagy was investigated in cell lines originated from iCC (HuH-28), eCC (TFK-1) and HCC (HepG2) by treating the cells with chloroquine (CQ) for inhibition and with Rapamycin, 5-Fluorouracil (5-FU) and Sorafenib for induction of autophagy. Our results indicated an inhibited autophagy in iCC and pCC tumor tissues, whereas active autophagy seemed to occur in dCC, especially in samples displaying low Ki-67 index. Additionally, low level of Beclin1 and high level of Ki-67 were associated with poor overall survival in dCC, suggesting the prognostic role of these proteins in dCC. Beside a baseline autophagy detected in each cell line, Rapamycin and 5-FU induced autophagy in iCC and HepG2 cell lines, Sorafenib in iCC cells. A chemotherapy agent in combination with CQ decreased IC50 effectively in the cell lines where basal and/or induced autophagy were present. In conclusion, we revealed differences in the autophagy activities of CC tissues and cell lines originated from different anatomical locations, which might influence patients' treatment. Our results also suggest a prognostic role of Beclin1 and Ki-67 in dCC.

Cancer-Associated Fibroblast-Derived IL-6 Determines Unfavorable Prognosis in Cholangiocarcinoma by Affecting Autophagy-Associated Chemoresponse

Simple Summary

We aimed to validate with clinical and molecular data the hypothesis that CAF infiltration and release of IL-6 predict poor prognosis in CCA patients following dysregulation of autophagy in cancer cells. Stromal IL-6 and cancer-cell-associated autophagy proteins were assayed by Tissue MicroArray immunohistochemistry and their expression correlated with overall survival (OS) in a cohort of 70 CCA patients. We found that patients bearing a CCA with low stromal IL-6 and active autophagy flux in the cancer cells have the best prognosis and this correlates with a more effective response to post-operative chemotherapy. A similar trend was observed in CCA patients from the TCGA database. In vitro experiments with primary CAFs isolated from human CCA showed that IL-6 impairs the autophagy-associated apoptotic response to 5-FU in human CCA cells. Stromal IL-6 inhibition of autophagy in cancer cells was confirmed in an animal model of CCA. Our data support a therapeutic strategy that includes drugs limiting the stromal inflammation and enhancing autophagy to improve the survival of CCA patients.

Abstract

Background: Interleukin-6 (IL-6) released by cancer-associated fibroblasts (CAFs) has been shown to associate with the malignant behavior of cholangiocarcinoma (CCA). Here, we aimed to validate with clinical and molecular data the hypothesis that CAF infiltration and release of IL-6 predict poor prognosis in CCA patients following dysregulation of autophagy in cancer cells. Methods: Stromal IL-6 and cancer-cell-associated autophagy proteins LC3 and p62 were assayed by Tissue MicroArray immunohistochemistry and their expression correlated with overall survival (OS) in a cohort of 70 CCA patients. The 5-FU cytotoxicity and autophagy were determined in CCA cells cultured with CAF-conditioned medium. Results: We show that patients bearing a CCA with low production of stromal IL-6 and active autophagy flux in the cancer cells have the best prognosis and this correlates with a more effective response to post-operative chemotherapy. A similar trend was observed in CCA patients from the TCGA database. In vitro genetic manipulation of IL-6 production by primary CAFs isolated from human CCA showed that IL-6 impairs the autophagy-associated apoptotic response to 5-FU in human CCA cells. Stromal IL-6 inhibition of autophagy in cancer cells was confirmed in an animal model of CCA. Conclusion: Our data support a therapeutic strategy that includes autophagy-enhancing drugs along with adjuvants limiting the stromal inflammation (i.e., the secretion of IL-6) to improve the survival of CCA patients.

Autophagy in liver diseases

Autophagy is the liver cell energy recycling system regulating a variety of homeostatic mechanisms. Damaged organelles, lipids and proteins are degraded in the lysosomes and their elements are re-used by the cell. Investigations on autophagy have led to the award of two Nobel Prizes and a health of important reports. In this review we describe the fundamental functions of autophagy in the liver including new data on the regulation of autophagy. Moreover we emphasize the fact that autophagy acts like a two edge sword in many occasions with the most prominent paradigm being its involvement in the initiation and progress of hepatocellular carcinoma. We also focused to the implication of autophagy and its specialized forms of lipophagy and mitophagy in the pathogenesis of various liver diseases. We analyzed autophagy not only in well studied diseases, like alcoholic and nonalcoholic fatty liver and liver fibrosis but also in viral hepatitis, biliary diseases, autoimmune hepatitis and rare diseases including inherited metabolic diseases and also acetaminophene hepatotoxicity. We also stressed the different consequences that activation or impairment of autophagy may have in hepatocytes as opposed to Kupffer cells, sinusoidal endothelial cells or hepatic stellate cells. Finally, we analyzed the limited clinical data compared to the extensive experimental evidence and the possible future therapeutic interventions based on autophagy manipulation.

Therapeutic Potential of Autophagy Modulation in Cholangiocarcinoma

Autophagy is a multistep catabolic process through which misfolded, aggregated or mutated proteins and damaged organelles are internalized in membrane vesicles called autophagosomes and ultimately fused to lysosomes for degradation of sequestered components. The multistep nature of the process offers multiple regulation points prone to be deregulated and cause different human diseases but also offers multiple targetable points for designing therapeutic strategies. Cancer cells have evolved to use autophagy as an adaptive mechanism to survive under extremely stressful conditions within the tumor microenvironment, but also to increase invasiveness and resistance to anticancer drugs such as chemotherapy. This review collects clinical evidence of autophagy deregulation during cholangiocarcinogenesis together with preclinical reports evaluating compounds that modulate autophagy to induce cholangiocarcinoma (CCA) cell death. Altogether, experimental data suggest an impairment of autophagy during initial steps of CCA development and increased expression of autophagy markers on established tumors and in invasive phenotypes. Preclinical efficacy of autophagy modulators promoting CCA cell death, reducing invasiveness capacity and resensitizing CCA cells to chemotherapy open novel therapeutic avenues to design more specific and efficient strategies to treat this aggressive cancer.

The Role of Beclin 1-Dependent Autophagy in Cancer

Autophagy (self-eating) is an intracellular degradation process used by cells to keep a “clean house”; as it degrades abnormal or damaged proteins and organelles, it helps to fight infections and also provides energy in times of fasting or exercising. Autophagy also plays a role in cancer, although its precise function in each cancer type is still obscure, and whether autophagy plays a protecting (through the clearing of damaged organelles and protein aggregates and preventing DNA damage) or a promoting (by fueling the already stablished tumor) role in cancer remains to be fully characterized. Beclin 1, the mammalian ortholog of yeast Atg6/Vps30, is an essential autophagy protein and has been shown to play a role in tumor suppression. Here, an update of the tumorigenesis regulation by Beclin 1-dependent autophagy is provided.

Diagnostic and prognostic biomarkers in cholangiocarcinoma

The high mortality rate of cholangiocarcinoma (CCA) is due, in part, to the lack of non-invasive approaches able to accurately detect this silent tumour at early stages, when therapeutic options can be potentially curative or may at least increase the overall survival of patients. The fact that the majority of CCA tumours are not linked to any known aetiological factor highly compromises the monitoring of patients at risk for tumour development and also their early diagnosis. Combination of clinical/biochemical features, imaging techniques and analysis of non-specific tumour biomarkers in serum are commonly used to help in the diagnosis of CCA, but tumour biopsy is usually required to confirm the diagnosis. Moreover, no prognostic biomarkers are currently used in the clinical setting, deserving more innovative research, and international validation and consensus. Important efforts have been made in the last few years to identify accurate non-invasive biomarkers, by using innovative techniques and high-throughput omics technologies. This review summarizes and discusses the advances in the investigation of novel diagnostic and prognostic biomarkers in CCA and envisions the future directions in this field of research.

High Beclin-1 and ARID1A expression corelates with poor survival and high recurrence in intrahepatic cholangiocarcinoma: a histopathological retrospective study

Background

Although surgical resection provides a cure for patients with intrahepatic cholangiocarcinoma (ICC), the risk of mortality and recurrence remains high. Several biomarkers are reported to be associated with the prognosis of ICC, including Beclin-1, ARID1A, carbonic anhydrase IX (CA9) and isocitrate dehydrogenase 1 (IDH1), but results are inconsistent. Therefore, a histopathological retrospective study was performed to simultaneously investigate the relationship of these four potential biomarkers with clinicopathological parameters and their prognostic values in patients with ICC.

Methods

A total of 113 patients with ICC were enrolled from Cancer Hospital of Chinese Academy of Medical Sciences between January 1999 and June 2015. The expression of Beclin-1, ARID1A, IDH1 and CA9 were determined by immunohistochemical staining. The prognostic values of the four biomarkers were analyzed by Cox regression and the Kaplan-Meier method.

Results

Beclin-1, ARID1A, CA9 and IDH1 were highly expressed in ICC tumor tissues. Higher mortality was positively associated with Beclin-1 expression (HR = 2.39, 95% CI = 1.09–5.24) and higher recurrence was positively associated with ARID1A expression (HR = 1.71, 95% CI = 1.06–2.78). Neither CA9 nor IDH1 expression was significantly associated with mortality or disease recurrence. Kaplan-Meier survival curves showed that ICC patients with higher Beclin-1 and ARID1A expression had a lower survival rate and a worse recurrence rate than patients with low Beclin-1 and ARID1A expression (p < 0.05).

Conclusions

High Beclin-1 and ARIDIA expression are strongly associated with poor prognosis in ICC patients, and thus Beclin-1 and ARID1A should be simultaneously considered as potential prognostic biomarkers for ICC patients.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5429-3) contains supplementary material, which is available to authorized users.

Diverse Functions of Autophagy in Liver Physiology and Liver Diseases

Autophagy is a catabolic process by which eukaryotic cells eliminate cytosolic materials through vacuole-mediated sequestration and subsequent delivery to lysosomes for degradation, thus maintaining cellular homeostasis and the integrity of organelles. Autophagy has emerged as playing a critical role in the regulation of liver physiology and the balancing of liver metabolism. Conversely, numerous recent studies have indicated that autophagy may disease-dependently participate in the pathogenesis of liver diseases, such as liver hepatitis, steatosis, fibrosis, cirrhosis, and hepatocellular carcinoma. This review summarizes the current knowledge on the functions of autophagy in hepatic metabolism and the contribution of autophagy to the pathophysiology of liver-related diseases. Moreover, the impacts of autophagy modulation on the amelioration of the development and progression of liver diseases are also discussed.

Dihydroartemisinin induces apoptosis and autophagy-dependent cell death in cholangiocarcinoma through a DAPK1-BECLIN1 pathway

Cholangiocarcinoma (CCA) is a very aggressive cancer arising from the malignant transformation of cholangiocytes. Intrahepatic CCA is associated with reactive inflammation and intense fibrosis of the hepatobiliary tract. Dihydroartemisinin (DHA), the active compound found in Artemisia annua, has been shown to possess anti-tumor activity in a variety of human cancers, including hepatoma. Here, we tested the ability of DHA to specifically kill CCA cells and have investigated the underlying mechanisms. DHA induced both apoptosis and autophagy-dependent caspase-independent cell death in many CCA cell lines, while being slightly toxic to immortalized cholangiocytes. DHA induced the expression of many apoptosis- and autophagy-related genes in CCA cells. In particular, it greatly induced the expression of DAPK1, and reduced the interaction of BECLIN1 with BCL-2 while promoting its interaction with PI3KC3. Genetic silencing of DAPK1 prevented DHA-induced autophagy. Pharmacologic and genetic inhibition of BECLIN1 function prevented autophagy and cell death induced by DHA in CCA cells. These data unravel a novel pathway of DHA cancer toxicity and open the possibility to introduce DHA in the therapeutic regimen for the treatment of CCA.

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.

The different roles of selective autophagic protein degradation in mammalian cells

Autophagy is an intracellular pathway for bulk protein degradation and the removal of damaged organelles by lysosomes. Autophagy was previously thought to be unselective; however, studies have increasingly confirmed that autophagy-mediated protein degradation is highly regulated. Abnormal autophagic protein degradation has been associated with multiple human diseases such as cancer, neurological disability and cardiovascular disease; therefore, further elucidation of protein degradation by autophagy may be beneficial for protein-based clinical therapies. Macroautophagy and chaperone-mediated autophagy (CMA) can both participate in selective protein degradation in mammalian cells, but the process is quite different in each case. Here, we summarize the various types of macroautophagy and CMA involved in determining protein degradation. For this summary, we divide the autophagic protein degradation pathways into four categories: the post-translational modification dependent and independent CMA pathways and the ubiquitin dependent and independent macroautophagy pathways, and describe how some non-canonical pathways and modifications such as phosphorylation, acetylation and arginylation can influence protein degradation by the autophagy lysosome system (ALS). Finally, we comment on why autophagy can serve as either diagnostics or therapeutic targets in different human diseases.

Effect of beclin 1 expression on the biological behavior and chemotherapy sensitivity of cervical cancer cells

The present study aimed to evaluate the effect of the expression of the autophagic gene beclin 1 on the biological behavior and chemotherapy sensitivity towards Taxol^® of cervical cancer HeLa cells. A beclin 1 expression vector was constructed and tranfected into HeLa cells. Reverse transcription-polymerase chain reaction and western blotting were used to detect the expression of beclin 1. Cell proliferation was detected based on the growth curve of the cells. The effect of beclin 1 expression on cell apoptosis was analyzed using Hoechst 33258 staining, which enabled to observe the morphology of apoptotic cells. Apoptosis-associated proteins were measured by western blot assay. The sensitivity of HeLa cells to Taxol^® was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Beclin 1 expression at the messenger RNA and protein levels was elevated following transfection of the beclin 1 expression plasmid (P<0.05). Hoechst 33258 staining revealed that the apoptosis rate of the transfected HeLa cells was significantly higher than that of normal HeLa cells. The expression of caspase-3 was increased in the transfected cells, and beclin 1 transfection increased B-cell lymphoma 2 (Bcl-2)-associated X protein (Bax):Bcl-2 ratio, resulting in Bax activation and Bcl-2 suppression (P<0.05). Chemotherapy sensitivity analysis demonstrated that the half maximal inhibitory concentration values of Taxol^® of the transfection, non-transfection and mock-vehicle groups were 30.4, 118.0 and 125.5 µg/ml, respectively. Beclin 1 inhibited proliferation and increased apoptosis of HeLa cells, and also increased the chemosensitivity of these cells to Taxol^®. The present results confirmed that beclin 1 is a favorable prognostic biomarker for cervical cancer treatment, and may serve to identify particular patients for individual therapy.

Coding-noncoding gene expression in intrahepatic cholangiocarcinoma

Recent studies have shown that long noncoding RNAs (lncRNAs) play crucial roles in human cancers. However, the function of lncRNAs and their downstream mechanisms are largely unknown in the molecular pathogenesis of intrahepatic cholangiocarcinoma (ICC). In the present study, we performed transcriptomic profiling of ICC and paired adjacent noncancerous tissues (N) by using lncRNA and messenger RNA (mRNA) microarrays. Quantitative real-time polymerase chain reaction was used to validate the microarray results. We tested for correlations between the expression levels of lncRNAs and target genes. Clinicopathologic characteristics and overall survival were compared using the t test and the Kaplan-Meier method, respectively. A total of 2773 lncRNAs were significantly upregulated in ICC tissues compared with the noncancerous tissues, whereas 2392 lncRNAs were downregulated. Bioinformatic analysis indicated that most of the genes were involved in carcinogenesis, hepatic system diseases, and signal transductions. Positive correlations were found between 4 lncRNA-mRNA pairs (RNA43085 and SULF1, RNA47504 and KDM8, RNA58630 and PCSK6, and RNA40057 and CYP2D6). When the clinicopathologic characteristics were accounted for, the cumulative overall survival rate was found to be associated with low expression levels of CYP2D6 (P = 0.005) and PCSK6 (P = 0.038). Patients with high expression levels of CYP2D6 and RNA40057 had a better prognosis (P = 0.014). Our results suggested that the lncRNA expression profiling in ICC tissues is profoundly different from that in noncancerous tissues. Thus, lncRNA may be a potential diagnostic and prognostic biomarker for ICC. Furthermore, the combined assessment of lncRNA and mRNA expressions might predict the survival of patients with ICC.

Autophagy in cholangiocarcinoma

Autophagy is a process through which cells utilize lysosomal hydrolases to degrade abnormal proteins and damaged organelles. This process allows cells to reuse degradation products and degrade harmful substances to maintain intracellular stability. Autophagy is normally maintained at a low level. Cells under unfavorable conditions activate autophagy to cope with unfavorable adverse factors. Autophagy participates in many physiological and pathological processes, such as cell aging, bacterial invasion, neurodegenerative diseases, apoptosis and tumor development. Autophagy also plays important roles in tumorigenesis, tumor progression, metastasis, relapse, and drug resistance of a variety of tumors including cholangiocarcinoma. However, the detailed mechanisms remain unclear. Analysis of the mechanism and regulation of autophagy in the genesis and development of cholangiocarcinoma has important significance and application value. This review summarizes the advances in research of autophagy in cholangiocarcinoma.

Autophagy may occur at an early stage of cholangiocarcinogenesis via biliary intraepithelial neoplasia

Similar to the pancreatic carcinoma sequence model, cholangiocarcinoma reportedly follows a stepwise carcinogenesis process via the precursor lesion biliary intraepithelial neoplasia (BilIN). Given that autophagy plays an important role in the occurrence and development of carcinomas, we examined the involvement of autophagy in multistep cholangiocarcinogenesis. Thirty-six patients with hepatolithiasis associated with BilIN and/or cholangiocarcinoma, 7 with intrahepatic cholangiocarcinoma, 8 with intraductal papillary neoplasm of the bile duct (IPNB), and 6 with control livers were surveyed. Their lesions were categorized as follows: invasive carcinoma (n = 16), IPNB (n = 8), BIlN-3 (n = 16), BilIN-1/2 (n = 40), nonneoplastic large bile duct (n = 55), and peribiliary gland (n = 55). We examined the immunohistochemical expression of autophagy-related proteins, microtubule-associated proteins light chain 3β (LC3), beclin-1, and p62/sequestosome-1 (p62), as well as tumor suppressor gene product p53. The extent of expression was semiquantitatively assessed. The status of KRAS mutations at codons 12 and 13 was examined in selected cases of BilIN-1/2. The expression of LC3 (cytoplasmic), beclin-1 (cytoplasmic), and p62 (cytoplasmic and nuclear) was significantly higher in BilIN-1/2, BilIN-3, IPNB, and invasive carcinoma than in large bile duct and peribiliary gland (P < .01). KRAS mutation was detected in 6 (40%) of 15 BilIN-1/2 lesions, and there was no correlation between the status of KRAS mutation and the expression of autophagy-related proteins. In conclusion, this study is the first to disclose that the expression of autophagy-related proteins, LC3, beclin-1, and p62, was increased at an early stage of multistep cholangiocarcinogenesis in hepatolithiasis. Autophagy, probably deregulated autophagy, may be related to the occurrence and development of cholangiocarcinoma.

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.

Autophagy may promote carcinoma cell invasion and correlate with poor prognosis in cholangiocarcinoma

The role of autophagy in cholangiocarcinoma is poorly understood. This study investigated its involvement in cholangiocarcinoma, focusing on carcinoma cell invasion and prognostic significance using cholangiocarcinoma cell lines, CCKS1 and HuCCT1, and human tissues of hilar and extrahepatic cholangiocarcinoma. Nutrient starvation induced the expression of LC3-II and the formation of LC3 puncta in both CCKS1 and HuCCT1, suggesting the occurrence of autophagy. The induction of autophagy was accompanied by the increased expression of an autophagy-related protein, Ambra1, in the cells. Under starvation conditions, the invasive activity of both cells was significantly increased, and a lysosomal inhibitor, chloroquine, attenuated this increased invasive activity. Transforming growth factor-β1 (TGF-β1), known as an inducer of epithelial-mesenchymal transition (EMT), increased the invasive activity of both cells, and chloroquine also significantly reduced TGF-β1-induced cell invasion. Immunohistochemical staining using cholangiocarcinoma tissues showed that the expression of Ambra1 positively correlated with the expression of Snail, one of the major transcriptional factors of EMT. In addition, overexpression of Ambra1 significantly correlated with lymph node metastasis and poor survival rate of the patients. These results suggest that the occurrence of autophagy may be associated with a malignant phenotype and poor prognosis in cholangiocarcinoma, and autophagy is possibly involved in EMT-related cholangiocarcinoma cell invasion.