Decreased Beclin-1 expression is correlated with the growth of the primary tumor in patients with squamous cell carcinoma and adenocarcinoma of the lung

Beclin 1, LC3 and P62 Expression in Equine Sarcoids

Simple Summary

Equine sarcoids, caused by bovine papillomaviruses, are equine skin tumors of fibroblastic origin. It is well known that bovine papillomaviruses are able to interfere with the survival and proliferation of cells by regulating autophagy, a mechanism implicated in the breakdown and reuse of old and damaged cellular material. The present study focused on the evaluation in equine sarcoids and normal skins of the expression level of some of the main proteins involved in the autophagic pathway, such as Beclin 1, LC3 and P62, by immunohistochemical and biochemical techniques. Results obtained in equine sarcoids suggested an alteration of the autophagic process which could lead to a predominance of a particular population of fibroblast. Those fibroblasts could survive longer in a hypoxic microenvironment and produce more and/or altered collagen, giving an origin to the equine sarcoid.

Abstract

Background: It is well known that δ-bovine papillomaviruses (BPV-1, BPV-2 and BPV-13) are one of the major causative agents of equine sarcoids, the most common equine skin tumors. Different viruses, including papillomaviruses, evolved ingenious strategies to modulate autophagy, a complex process involved in degradation and recycling of old and damaged material. Methods: The aim of this study was to evaluate, by immunohistochemistry (IHC) and Western blot (WB) analysis, the expression of the main related autophagy proteins (Beclin 1, protein light chain 3 (LC3) and P62), in 35 BPV1/2 positive equine sarcoids and 5 BPV negative normal skin samples. Results: Sarcoid samples showed from strong-to-moderate cytoplasmic immunostaining, respectively, for Beclin 1 and P62 in >60% of neoplastic fibroblasts, while LC3 immunostaining was weak to moderate in ≤60% of neoplastic fibroblasts. Western blot analysis confirmed the specificity of the antibodies and revealed no activation of autophagic flux despite Beclin 1 overexpression in sarcoid samples. Conclusion: Results could suggest the activation of the initial phase of autophagy in equine sarcoids, and its impairment during the following steps. The impairment of autophagy could lead to a selection of a quiescent population of fibroblasts, which survive longer in a hypoxic microenvironment and produced more and/or altered collagen.

The roles, controversies, and combination therapies of autophagy in lung cancer

Lung cancer is one of the leading causes of death among men and women worldwide. The disease initially has a silent phenotype, which leads to the progression of the disease and ultimately the lack of proper response to routine treatments. Autophagy, known as an intracellular "recycle bin" for the degradation of defective proteins and molecules, is one of the mechanisms that has been considered in the context of cancer in recent years. This study aims to provide a comprehensive review of published articles on autophagy in the context of lung cancer to have a complete view of the role of autophagy in lung cancer and its possible treatments. PubMed, Scopus, and Google Scholar were searched until June 15 to find related articles. No specific search filters or restrictions were applied. The results were entered into reference management software for aggregation and management. The full text of all articles was screened and studied. In conclusion, studies on the exact function of autophagy in lung cancer are contradictory, but what can be concluded from a review of literature on lung cancer is that targeting autophagy combined with traditional routine therapies such as chemotherapy, especially in advanced stages of lung cancer, can be an effective anticancer approach.

The Anticancer Action of a Novel 1,2,4-Triazine Sulfonamide Derivative in Colon Cancer Cells

Cancer therapy is one of the most important challenges of modern medical and chemical sciences. Among the many methods of combating cancer, chemotherapy plays a special role. Imperfect modern chemotherapy justifies continuing the search for new, more effective, and safe drugs. Sulfonamides are the classic group of chemotherapeutic drugs with a broad spectrum of pharmacological activity. Recent literature reports show that sulfonamide derivatives have anti-tumor activity in vitro and in vivo. The aim of the study was to synthesize a novel 1,2,4-triazine sulfonamide derivative and check its anticancer potential in DLD-1 and HT-29 colon cancer cells. The biological studies included MTT assay, DNA biosynthesis, cell cycle analysis, Annexin V binding assay, ethidium bromide/acridine orange staining, and caspase-8, -9, and -3/7 activity. The concentrations of important molecules (sICAM-1, mTOR, Beclin-1, cathepsin B) involved in the pathogenesis and poor prognosis of colorectal cancer were also evaluated by ELISA. We demonstrated that the novel compound was able to induce apoptosis through intrinsic and extrinsic pathways and was capable of decreasing sICAM-1, mTOR, cathepsin B concentrations, whereas increased Beclin-1 concentration was detected in both colon cancer cell lines. The novel compound represents promising multi-targeted potential in colorectal cancer, but further in vivo examinations are needed to confirm the claim.

Autophagy and pulmonary disease

Autophagy is a process of cell self-renewal that is dependent on the degradation of the cytoplasmic proteins or organelles of lysosomes. Many diseases, such as metabolic diseases, cancer, neurodegenerative diseases, and lung diseases, have been confirmed to be associated with elevated or impaired levels of autophagy. At present, studies have found that autophagy participates in the regulation of chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis, pulmonary hypertension, acute lung injury, lung cancer, and other pulmonary diseases. Using recent literature on the signal transduction mechanisms of autophagy and the effects of autophagy signalling on lung diseases, this review intends to clarify the mechanisms of lung disease to guide the treatment of related diseases. The reviews of this paper are available via the supplemental material section.

Effects of Beclin 1 overexpression on aggressive phenotypes of colon cancer cells

Beclin 1 is involved in autophagy, differentiation, apoptosis and cancer progression, and functions as a haploinsufficient tumor suppressor gene. The aim of the present study was to elucidate the function of Beclin 1 in colon cancer. A Beclin 1-expressing plasmid was transfected into HCT-15 and HCT-116 cells, and the phenotypes and associated molecules were determined. Beclin 1 transfectants were subcutaneously injected into nude mice to determine tumor growth, and proliferation and apoptosis levels using Ki-67 immunostaining and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL), respectively. Beclin 1 overexpression inhibited viability as determined using a Cell Counting Kit-8 assay, inhibited migration and invasion as determined using a wound healing assay or Transwell assay, and lamellipodia formation by filamentous actin staining, induced autophagy as determined using electron microscopy, and light chain 3B (LC-3B) expression, and apoptosis as determined using Annexin V staining in the two cell lines (P<0.05). Beclin 1 induced G₂ arrest of HCT-15 transfectants as determined using propidium iodide staining (P<0.05), whereas HCT-116 transfectants were arrested in G₁ phase (P<0.05). The two transfectants exhibited increased expression of c-Myc, cyclin D1, β-catenin, insulin-response element 1 and 78 kDa glucose-regulated protein compared with the control and mock cells as determined using the reverse transcription-quantitative polymerase chain reaction (P<0.05). Beclin 1 overexpression upregulated LC-3B and cyclin-dependent kinase 4 expression, but downregulated cyclin E expression of the cancer cell lines as determined using western blot analysis (P<0.05). Beclin 1 expression in vivo significantly suppressed the proliferation of colon cancer cells in xenograft models via inducing apoptosis by TUNEL, and inhibiting proliferation by Ki-67 expression (P<0.05). Beclin 1 overexpression may reverse aggressive phenotypes and suppress colon cancer tumor growth, and be employed as a target molecule for gene therapy of patients with colon cancer.

A novel combined score of biomarkers in sputum may be an indicator for lung cancer: A pilot study

BACKGROUND

Lung cancer is a leading cause of morbidity and mortality worldwide and there is an urgent need for sensitive, specific, and reliable biomarkers.

METHODS

The study population included 60 patients (31 with lung cancer and 29 with chronic obstructive pulmonary disease [COPD]) and thirty healthy individuals comprised the control group. Measurements of neutrophil, beclin-1, VEGF, ICAM, VCAM, and TNF-alpha levels in induced sputum were analyzed as possible biomarkers for lung cancer.

RESULTS

Neutrophil, beclin-1, VEGF, ICAM and TNF-alpha levels of lung cancer patients differed significantly compared to those of COPD patients and healthy controls. A novel combined-score was created which was found to increase the likelihood to belong to the cancer group by 70% (odds-ratio 1.70 CI = 1.310-2.224,p < 0.001).

CONCLUSION

Biomarkers of autophagy, angiogenesis and inflammation in lung-cancer patients are significantly different from controls, and combination of these markers may be an indicator for lung cancer.

Prognostic and clinicopathological significance of Beclin-1 in non-small-cell lung cancer: a meta-analysis

Background

Autophagy plays a key role in the development of non-small-cell lung cancer (NSCLC). Beclin-1 is essential for the initiation and regulation of autophagy. Accumulated studies have investigated the prognostic role of Beclin-1 in NSCLC, but conclusions remain controversial. Therefore, we conducted this meta-analysis to assess the potential significance of Beclin-1 in NSCLC.

Materials and methods

PubMed and Embase databases were searched for eligible studies published before December 31, 2017. Odds ratio (OR) was pooled to evaluate the clinicopathological significance of Beclin-1 in NSCLC. Hazard ratio (HR) was adopted to assess the association of Beclin-1 with overall survival (OS).

Results

Eight studies involving 1,159 patients were included in this meta-analysis. The pooled results showed that high Beclin-1 expression was significantly correlated with earlier tumor grade (OR=0.54, 95% CI: 0.36-0.81, P=0.003), less nodal involvement (OR=0.56, 95% CI: 0.37-0.86, P=0.007), earlier TNM stage (OR=0.62, 95% CI: 0.43-0.89, P=0.010), smaller tumor size (OR=0.54, 95% CI: 0.36-0.81, P=0.003), better differentiation (OR=0.48, 95% CI: 0.36-0.64, P<0.001), and less recurrence (OR=0.24, 95% CI: 0.14-0.41, P<0.001). Moreover, high level of Beclin-1 was significantly associated with better OS in NSCLC (HR=0.41, 95% CI: 0.26-0.64, P<0.001).

Conclusion

Our meta-analysis suggests that high Beclin-1 expression predicts a better clinicopathological status and a better prognosis in NSCLC. Beclin-1 might act as a promising prognostic biomarker for NSCLC.

Immunohistochemical profiling of receptor tyrosine kinases, MED12, and TGF-βRII of surgically resected small cell lung cancer, and the potential of c-kit as a prognostic marker

The limited number of available treatments for patients with small-cell lung cancer (SCLC) has prompted us to further investigate the biology of SCLC by molecular profiling. We collected formalin-fixed paraffin-embedded tumor samples from 127 patients with SCLC, who had undergone surgery at 16 institutions between January 2003 and January 2013, and analyzed the association between disease-specific survival and protein expression of c-kit, c-Met, epidermal growth factor receptor, human EGFR-related 2, vascular endothelial growth factor receptor II, anaplastic lymphoma kinase, mediator complex subunit 12 (MED12), and transforming growth factor beta receptor II (TGF-βRII) by immunohistochemistry (IHC). Of the 125 evaluable samples, all tumors expressed MED12, and 123 samples (98.4%) expressed TGF-βRII. MED12 was highly expressed in the nucleus in 92% of the positive samples while TGF-βRII was highly expressed in the cytoplasm in 55% of the positive samples. High c-kit expression was an independent favorable prognostic marker confirmed by multivariate analysis (hazard ratio: 0.543, 95% confidence interval: 0.310-0.953, p = 0.033). Both the relapse free-survival and overall survival of patients who underwent adjuvant chemotherapy were statistically longer in those with high c-kit expression (n = 38) than those with intermediate, low, or no c-kit expression (n = 19) (not reached vs 11.6 months, p = 0.021; not reached vs 25.9 months, p = 0.028). IHC for c-kit may offer a prognostic marker for early-stage SCLC, and the results for MED12 and TGF-βRII may suggest the biological characteristics of SCLC. Further investigation of the roles of their related molecules in early stage SCLC is required.

Decreased expression of Beclin‑1 is significantly associated with a poor prognosis in oral tongue squamous cell carcinoma

The autophagy-related gene Beclin-1 is critical in the regulation of tumourigenesis and progression, but its role in oral tongue squamous cell carcinoma (OTSCC) has not yet been reported. This study aimed to investigate Beclin-1 expression and its significance in OTSCC. Beclin-1 expression was assessed by reverse transcription-quantitative polymerase chain reaction or western blot analysis in 14 OTSCC tissues and matched adjacent noncancerous tissues as well as in 5 OTSCC cell lines and a normal tongue epithelial cell line. Beclin-1 protein expression was examined by immunohistochemistry in 133 OTSCC specimens, and the correlation between Beclin-1 expression and clinicopathological features was investigated. Furthermore, MTT and colony formation assays were performed to investigate the effect of Beclin-1 on the proliferation and clonogenicity of OTSCC cells. It was demonstrated that Beclin-1 expression was significantly decreased in the majority of the 14 OTSCC tissues and the 5 OTSCC cell lines relative to the matched non-cancerous tissues and the normal tongue epithelial cell line, respectively. Immunohistochemistry analysis revealed that decreased Beclin-1 expression was significantly correlated with poor differentiation, lymph node metastasis, advanced clinical tumour-node-metastasis stage, and a poor prognosis in patients with OTSCC. The in vitro assays indicated that the overexpression of Beclin-1 significantly inhibits the proliferation and clonogenicity of OTSCC cells. These results demonstrate that Beclin-1 acts as a tumour suppressor in the development or progression of OTSCC and that Beclin-1 may represent a novel prognostic marker for patients with OTSCC.

Expression and clinical significance of Beclin-1 in gastric cancer tissues of various clinical stages

Autophagy is a common phenomenon in cancer metabolism. However the mechanism and guiding significance of autophagy in the development of gastric cancer has remained to be elucidated. In the present study, 75 gastric cancer tissue specimens were collected at The China Japan Union Hospital of Jilin University (Changchun, China). Of these samples, 16 cases were stage 1, 40 stage 2 and 19 stage 3. Polymerase chain reaction and western blotting were used to detect the messenger RNA and protein expression of Beclin-1, a significant protein associated with cellular autophagy. It was found that expression of Beclin-1 in cancer tissues from stages 1 and 2 was higher, while in stage 3 cases levels were significantly lower than that of adjacent normal tissues. In addition, the infiltration of inflammatory cytokines was also increased in stage 1 and 2 cases. In vitro studies revealed that following stimulation with interferon-γ (IFN-γ), autophagy-associated proteins Beclin-1 and microtubule-associated protein light chain 3 were activated. Furthermore, activation of autophagy inhibited xenograft growth in nude mice. The results of these in vivo and in vitro experiments indicated that in gastric cancer tissues, autophagy was downregulated following the development of cancer tissue and that inflammation may be a significant factor in this process. IFN-γ may be involved in the mediation of this process and thus present a novel target for the treatment of gastric cancer.

Expression of Beclin Family Proteins Is Associated with Tumor Progression in Oral Cancer

Background

Beclin 1 and Beclin 2 are autophagy-related proteins that show similar amino acid sequences and domain structures. Beclin 1 established the first connection between autophagy and cancer. However, the role of Beclin 2 in cancer is unclear. The aims of this study were to analyze Beclin 1 and Beclin 2 expressions in oral cancer tissues and in cell lines, and to evaluate their possible roles in cancer progression.

Methods

We investigated Beclin 1 and Beclin 2 expressions by immunohistochemistry in 195 cases of oral cancer. The prognostic roles of Beclin 1 and Beclin 2 were analyzed statistically. In vitro, overexpression and knockdown of Beclin proteins were performed on an oral cancer cell line, SAS. The immunofluorescence and autophagy flux assays confirmed that Beclin proteins were involved in autophagy. The impacts of Beclin 1 and Beclin 2 on autophagy and tumor growth were evaluated by conversion of LC3-I to LC3-II and by clonogenic assays, respectively.

Results

Oral cancer tissues exhibited aberrant expressions of Beclin 1 and Beclin 2. The cytoplasmic Beclin 1 and Beclin 2 expressions were unrelated in oral cancer tissues. In survival analyses, high cytoplasmic Beclin 1 expression was associated with low disease specific survival, and negative nuclear Beclin 1 expression was associated with high recurrent free survival. Patients with either high or low cytoplasmic Beclin 2 expression had significantly lower overall survival and disease specific survival rates than those with moderate expression. In oral cancer cells, overexpression of either Beclin 1 or Beclin 2 led to autophagy activation and increased clonogenic survival; knockdown of Beclin 2 impaired autophagy and increased clonogenic survival.

Conclusions

Our results indicated that distinct patterns of Beclin 1 and Beclin 2 were associated with aggressive clinical outcomes. Beclin 1 overexpression, as well as Beclin 2 overexpression and depletion, contributed to tumor growth. These findings suggest Beclin proteins are associated with tumorigenesis.

Defective Beclin-1 and elevated hypoxia-inducible factor (HIF)-1α expression are closely linked to tumorigenesis, differentiation, and progression of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is an aggressive cancer with a poor prognosis. Autophagy and hypoxia have been involved in HCC tumorigenesis. In the present study, we examined the relationship between Beclin-1 expression and hypoxia-inducible factor (HIF)-1α expression in HCC by immunohistochemistry on 65 tumor specimens. Their correlations with clinicopathological features were also explored. There was a loss of Beclin-1 protein expression in 49.2 % of HCC. Beclin-1 expression was only significantly correlated with virus infection status (p = 0.025) and marginally associated with HCC grade (p = 0.057). Forty-two tumors (64.6 %) showed high HIF-1α expression, and it was significantly associated with large tumor size (p = 0.003), multifocal tumors (p = 0.038), and advanced stage (p = 0.043). Beclin-1 expression was significantly associated with HIF-1α expression (p = 0.001). HCC cases were further stratified according to their hypoxia status into hypoxic and normoxic groups. In the hypoxic group, Beclin-1 expression was negatively correlated with HCC high tumor grade (p < 0.001), advanced stage (p = 0.013), large size (p = 0.002), and multifocal tumors (p = 0.047). In the normoxic group, no significant relations between Beclin-1 expression and any of the clinicopathological parameters were identified. Our findings that reduced Beclin-1 and high HIF-1α expression are associated with the development and progression of HCC may provide molecular therapeutic targets toward inhibiting HCC development and progression.

Autophagy in lung disease pathogenesis and therapeutics

Autophagy, a cellular pathway for the degradation of damaged organelles and proteins, has gained increasing importance in human pulmonary diseases, both as a modulator of pathogenesis and as a potential therapeutic target. In this pathway, cytosolic cargos are sequestered into autophagosomes, which are delivered to the lysosomes where they are enzymatically degraded and then recycled as metabolic precursors. Autophagy exerts an important effector function in the regulation of inflammation, and immune system functions. Selective pathways for autophagic degradation of cargoes may have variable significance in disease pathogenesis. Among these, the autophagic clearance of bacteria (xenophagy) may represent a crucial host defense mechanism in the pathogenesis of sepsis and inflammatory diseases. Our recent studies indicate that the autophagic clearance of mitochondria, a potentially protective program, may aggravate the pathogenesis of chronic obstructive pulmonary disease by activating cell death programs. We report similar findings with respect to the autophagic clearance of cilia components, which can contribute to airways dysfunction in chronic lung disease. In certain diseases such as pulmonary hypertension, autophagy may confer protection by modulating proliferation and cell death. In other disorders, such as idiopathic pulmonary fibrosis and cystic fibrosis, impaired autophagy may contribute to pathogenesis. In lung cancer, autophagy has multiple consequences by limiting carcinogenesis, modulating therapeutic effectiveness, and promoting tumor cell survival. In this review we highlight the multiple functions of autophagy and its selective autophagy subtypes that may be of significance to the pathogenesis of human disease, with an emphasis on lung disease and therapeutics.

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Autophagy may impact the pathogenesis of pulmonary diseases.

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Mitophagy may exert deleterious effects in the pathogenesis of COPD.

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Autophagy can exert pleiotropic effects in lung cancer.

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Targeting autophagy may represent a promising therapeutic strategy in human diseases.

Immunohistochemical assessment of ATG7, LC3, and p62 in ameloblastomas

BACKGROUND

To investigate the roles of autophagy in tumorigenesis, cytodifferentiation, and prognosis of odontogenic tumors, we analyzed the immunohistochemical expression of ATG7, LC3, and p62 in odontogenic tissues.

METHODS

Tissue specimens of nine dental follicles and 69 ameloblastomas were immunohistochemically examined with antibodies against ATG7, LC3, and p62.

RESULTS

Immunohistochemical reactivity for ATG7, LC3, and p62 was detected in many odontogenic epithelial cells and several endothelial cells and fibroblasts in dental follicles and ameloblastomas. ATG7 reactivity in ameloblatomas was significantly higher than that in dental follicles. Expression of ATG7, LC3, and p62 was found markedly in neoplastic cells near the basement membrane rather than central polyhedral cells in ameloblastomas. Reactivity for these molecules was significantly higher in unicystic ameloblastomas than in solid ameloblastomas. Granular cells in granular cell ameloblastomas showed obvious reactivity for the autophagy- related molecules, and LC3 reactivity in granular cell ameloblastomas was significantly higher than in other ameloblastoma variations. Recurrent ameloblastomas showed significantly lower reactivity of LC3 and p62 than primary ameloblastomas.

CONCLUSIONS

Expression of ATG7, LC3, and p62 in dental follicles and ameloblastomas suggests that autophagy regulation might be affected by microenvironment alterations during tumorigenesis. The molecular machinery for autophagy is possibly involved in tissue architecture, neoplastic cell differentiation, and prognosis of the benign epithelial odontogenic tumor.

Prognostic significance of p62/SQSTM1 subcellular localization and LC3B in oral squamous cell carcinoma

Background:

Autophagy is a programmed cell survival mechanism that has a key role in both physiologic and pathologic conditions. The relationship between autophagy and cancer is complex because autophagy can act as either a tumour suppressor or as a tumour promoter. The role of autophagy in oral squamous cell carcinoma (OSCC) is controversial. Several studies have claimed that either a high or low expression of autophagy-related proteins was associated with poor prognosis of OSCCs. The aims of the study were to compare autophagy in OSCCs, verrucous hyperplasias, and normal oral mucosas, and to inspect the prognostic role of autophagy in OSCCs.

Methods:

We used the autophagosome marker, LC3B, and autophagy flux marker, p62/SQSTM1 (p62), by using immunohistochemistry, and examined p62 mRNA by RNA in situ hybridization, to evaluate autophagy in 195 OSCCs, 47 verrucous hyperplasias, and 37 normal oral mucosas. The prognostic roles of LC3B and p62 protein expressions in OSCCs were investigated.

Results:

We discovered that the normal oral mucosa exhibited limited LC3B punctae and weak cytoplasmic p62 staining, whereas the OSCCs exhibited a marked increase in LC3B punctae and cytoplasmic p62 expression. The expression pattern of LC3B and cytoplasmic p62 of the verrucous hyperplasias were between normal oral mucosas and OSCCs. The normal oral mucosas, verrucous hyperplasias, and OSCCs presented no differences in nuclear p62 expression and the p62 mRNA level. p62 mRNA expression was elevated in a minority of cases. High p62 mRNA expression was associated with high p62 protein expression in the cytoplasm. Increased LC3B punctae, high cytoplasmic p62, and low nuclear p62 expressions in OSCCs were associated with aggressive clinicopathologic features and unfavourable prognosis. In addition, low nuclear p62 expression was an independent prognostic factor for overall and disease-specific survival rates. Furthermore, we disclosed that high cytoplasmic p62 expression accompanied with either a low or high LC3B expression, which indicated autophagy impairment under basal or activated autophagic activity, was associated with aggressive behaviour in advanced OSCCs.

Conclusions:

We suggested that autophagy was altered during cancer initiation and progression. Autophagy impairment contributed to cancer progression in advanced OSCCs.

Expression of beclin 1 in non-small cell lung cancer: an immunohistochemical study

BACKGROUND

Cigarette smoking causes a variety of adverse human health effects, including lung cancer. The molecular events associated with smoke-induced carcinogenesis are thought to be related in part to autophagy. Beclin 1 is an important autophagy-related protein involved in cell death and cell survival.

AIM

The purpose of this investigation was to determine the beclin 1 protein and its association with cigarette smoke and the mutation of epidermal growth factor receptor (EGFR) in non-small cell lung cancer (NSCLC).

MATERIAL AND METHODOLOGY

Our study included 108 cases of non-small cell lung cancer who were admitted in our hospital. The beclin 1 protein was detected by immunohistochemistry and EGFR mutation by direct sequencing.

RESULTS

Beclin 1 expression could be detected in 15 (13.9%) of 108 specimens. These studies investigated that beclin 1 expression was associated with heavy smoking, the gender and the histological type of NSCLC (P = 0.023, 0.035 and 0.039). No association of beclin 1 with EGFR mutation was found (P > 0.05).

CONCLUSION

The results from these experiments indicate that heavy smoking may induce the beclin 1 protein in NSCLC.

The relation of beclin 1 and bcl-2 expressions in high grade prostatic intraepithelial neoplasia and prostate adenocarcinoma: a tissue microarray study

The aim of the present study was to evaluate the expressions of beclin 1 and bcl-2 in prostate cancer (PC) and high grade prostatic intraepithelial neoplasia (HGPIN), and to investigate their relationship with clinicopathological parameters. The study included 30 benign prostatic hyperplasia (BPH), 40 HGPIN and 106 primary PC cases. The expressions of beclin 1 and bcl-2 were assessed semiquantitatively based on both the percentage and intensity of positive staining cells. Beclin 1 was positive in 27 (90%) BPH, 37 (92.5%) HGPIN, and 90 (84.9%) PC cases (p>0.05). Bcl-2 immunostaining was detected in 99 (93.4%) PC, 37 (92.5%) HGPIN, and 9 (30%) BPH cases (p<0.0001). Regarding expression scores, beclin 1 was significantly lower in PC cases than in the HGPIN and BPH groups (p<0.0001), and it was also negatively correlated with Gleason score (p=0.004, r=-0.274). Bcl-2 expression score was significantly higher in PC than in the other groups (p<0.0001), and also positively correlated with Gleason score (p<0.0001, r=0.425). Furthermore, a negative correlation was found between bcl-2 and beclin 1 expression scores in PC cases (p=0.006, r=-0.265). Our results suggest an association between bcl-2 and beclin 1 expressions in malignant transformation of prostate tissue and also in regulating PC cell differentiation, progression and the aggressiveness of PC.

Autophagy and thyroid carcinogenesis: genetic and epigenetic links

Thyroid cancer is the most common cancer of the endocrine system and is responsible for the majority of deaths from endocrine malignancies. Although a large proportion of thyroid cancers belong to well differentiated histologic subtypes, which in general show a good prognosis after surgery and radioiodine ablation, the treatment of radio-resistant papillary-type, of undifferentiated anaplastic, and of medullary-type thyroid cancers remains unsatisfactory. Autophagy is a vesicular process for the lysosomal degradation of protein aggregates and of damaged or redundant organelles. Autophagy plays an important role in cell homeostasis, and there is evidence that this process is dysregulated in cancer cells. Recent in vitro preclinical studies have indicated that autophagy is involved in the cytotoxic response to chemotherapeutics in thyroid cancer cells. Indeed, several oncogenes and oncosuppressor genes implicated in thyroid carcinogenesis also play a role in the regulation of autophagy. In addition, some epigenetic modulators involved in thyroid carcinogenesis also influence autophagy. In this review, we highlight the genetic and epigenetic factors that mechanistically link thyroid carcinogenesis and autophagy, thus substantiating the rationale for an autophagy-targeted therapy of aggressive and radio-chemo-resistant thyroid cancers.

Autophagy: a crucial moderator of redox balance, inflammation, and apoptosis in lung disease

SIGNIFICANCE

Autophagy is a fundamental cellular process that functions in the turnover of subcellular organelles and protein. Activation of autophagy may represent a cellular defense against oxidative stress, or related conditions that cause accumulation of damaged proteins or organelles. Selective forms of autophagy can maintain organelle populations or remove aggregated proteins. Autophagy can increase survival during nutrient deficiency and play a multifunctional role in host defense, by promoting pathogen clearance and modulating innate and adaptive immune responses.

RECENT ADVANCES

Autophagy has been described as an inducible response to oxidative stress. Once believed to represent a random process, recent studies have defined selective mechanisms for cargo assimilation into autophagosomes. Such mechanisms may provide for protein aggregate detoxification and mitochondrial homeostasis during oxidative stress. Although long studied as a cellular phenomenon, recent advances implicate autophagy as a component of human diseases. Altered autophagy phenotypes have been observed in various human diseases, including lung diseases such as chronic obstructive lung disease, cystic fibrosis, pulmonary hypertension, and idiopathic pulmonary fibrosis.

CRITICAL ISSUES

Although autophagy can represent a pro-survival process, in particular, during nutrient starvation, its role in disease pathogenesis may be multifunctional and complex. The relationship of autophagy to programmed cell death pathways is incompletely defined and varies with model system.

FUTURE DIRECTIONS

Activation or inhibition of autophagy may be used to alter the progression of human diseases. Further resolution of the mechanisms by which autophagy impacts the initiation and progression of diseases may lead to the development of therapeutics specifically targeting this pathway.

Ursolic acid promotes cancer cell death by inducing Atg5-dependent autophagy

Ursolic acid (UA) has been reported to possess anticancer activities. Although some of the anticancer activities of UA have been explained by its apoptosis-inducing properties, the mechanisms underlying its anticancer actions are largely unknown. We have found that UA-activated autophagy induced cytotoxicity and reduced tumor growth of cervical cancer cells TC-1 in a concentration-dependent manner. UA did not induce apoptosis of TC-1 cells in vitro as determined by annexin V/propidium iodide staining, DNA fragmentation, and Western blot analysis of the apoptosis-related proteins. We found that UA increased punctate staining of light chain 3 (LC3), which is an autophagy marker. LC3II, the processed form of LC3I which is formed during the formation of double membranes, was induced by UA treatment. These results were further confirmed by transmission electron microscopy. Wortmannin, an inhibitor of autophagy, and a small interfering RNA (siRNA) for autophagy-related genes (Atg5) reduced LC3II and simultaneously increased the survival of TC-1 cells treated with UA. We also found that LC3II was significantly reduced and that survival was increased in Atg5-/- mouse embryonic fibroblast (MEF) cells compared to Atg5+/+ MEF cells under UA treatment. However, silencing BECN1 by siRNA affected neither the expression of LC3II nor the survival of TC-1 cells under UA treatment. These results suggest that autophagy is a major mechanism by which UA kills TC-1 cells. It is Atg5 rather than BECN1 that plays a crucial role in UA-induced autophagic cell death in TC-1 cells. The activation of autophagy by UA may become a potential cancer therapeutic strategy complementing the apoptosis-based therapies. Furthermore, regulation of Atg5 may improve the efficacy of UA in cancer treatment.

Autophagic protein Beclin 1 serves as an independent positive prognostic biomarker for non-small cell lung cancer

Beclin 1, a key regulator of autophagy, has been found to be aberrantly expressed in a variety of human malignancies. Herein, we employed immunohistochemistry (IHC) to detect the protein expression of Beclin 1 in non-small cell lung cancer (NSCLC) and paired normal adjacent lung tissues, and analyzed its clinicopathological/prognostic significance in NSCLC. Receiver operating characteristic (ROC) curve analysis was utilized to determine a cutoff point (>2 VS. ≤2) for Beclin 1 expression in a training set (n = 105). For validation, the ROC-derived cutoff value was subjected to analysis of the association of Beclin 1 with patients’ clinical characteristics and outcome in a testing set (n = 111) and the overall patient cohort (n = 216). Our data showed that Beclin 1 was significantly lower in NSCLC tissues compared with the adjacent normal tissues, negatively associating with tumor recurrence rate (65.8% VS 32.3%; p < 0.001). In the testing set and the overall patient cohort, low expression of Beclin 1 showed significantly inferior overall survival (OS) (p < 0.001) and progression-free survival (PFS) (p < 0.001) compared to high expression of Beclin 1. In the testing set and the overall patient cohort, the median duration of OS for patients with high and low expression of Beclin 1 was 108 VS. 24.5 months (p < 0.001) and 108 VS. 28 months (p < 0.001), respectively. Furthermore, low expression of Beclin 1 was also a poor prognostic factor within each stage of NSCLC patients. Multivariate analysis identified that Beclin 1 was an independent prognostic factor for NSCLC. Our findings in the present study provided evidence that Beclin 1 may thus emerge as an independent prognostic biomarker in this tumor entity in the future.

Beclin 1 and bcl-2 expressions in bladder urothelial tumors and their association with clinicopathological parameters

Beclin 1 plays a critical role in the regulation of autophagy, apoptosis, differentiation, as well as in the development and progression of cancer. The aim of this study was to examine the expression of beclin 1 and bcl-2 in bladder urothelial tumors, and to investigate the relationship between these two markers and clinicopathological parameters. Our study included 84 bladder urothelial tumors and 10 non-tumoral bladder tissues. Immunohistochemistry was performed on tissue microarray (TMA) sections and was evaluated semiquantitatively on the basis of the percentage of positively stained cells (proportion) and staining intensity. A significant association was found between the expression score of beclin 1 and pT stages of the urothelial tumors (p=0.012). Also, the level of beclin 1 expression inversely correlated with histological grade and pT stages (p=0.009, r=-0.284; p=0.001, r=-0.361, respectively). The bcl-2 expression level positively correlated with histological grade and pT stages of the urothelial tumors (p=0.026, r=0.243; p<0.0001, r=0.491, respectively). In addition, the level of beclin 1 expression tended to be inversely correlated with the bcl-2 expression level in urothelial tumors (p=0.055, r=-0.210). According to our data, down-regulation of beclin 1 expression and also bcl-2 overexpression seem to play an important role in the progression and aggressiveness of bladder urothelial tumors.

Expression of autophagy-related protein Beclin-1 in malignant canine mammary tumors

Background

Autophagy is a self-catabolic mechanism that degrades unnecessary cellular components through lysosomal enzymes. Beclin-1, an autophagy-related protein, establishes the first connection between autophagy and tumorigenesis. The purpose of this study is to assess the Beclin-1 expression pattern and to determine its prognostic significance in patients with malignant canine mammary tumor (CMT).

Results

We examined Beclin-1 expression in 70 cases of malignant CMTs by immunohistochemistry. Cytoplasmic Beclin-1 expression was significantly weaker in cancer cells than in nearby normal mammary glands (p < 0.001). Low cytoplasmic expression (57.14%) was associated with older age, lower degree of tubular formation, increased mitotic activity, higher histologic grade, and extensive necrosis. Low nuclear expression (40%) was connected with older age, lower degree of tubular formation, extensive necrosis, and negative for Her2/neu overexpression. Univariate survival analysis showed that Beclin-1 cytoplasmic expression was a poor prognostic factor for overall survival rate (p < 0.001). Multivariate survival analysis demonstrated that Beclin-1 cytoplasmic expression is an independent prognostic factor (p = 0.016).

Conclusions

Loss of Beclin-1 is associated with aggressive clinicopathologic features and poor overall survival. The results suggest that Beclin-1 plays an important role in tumor progression of malignant CMTs.

Low expression of Beclin 1 and elevated expression of HIF-1α refine distant metastasis risk and predict poor prognosis of ER-positive, HER2-negative breast cancer

Even though ER-positive, HER2-negative breast tumors represent a subset of breast cancers with a better clinical outcome, approximately 12.7 % of patients in this subgroup ultimately develop cancer-related mortality. Recent studies had confirmed that hypoxia-induced autophagy-related gene Beclin 1 expression might be important for disease progression and be correlated with patient outcome in several tumors. Here, we examined the autophagic Beclin 1 and hypoxic HIF-1α levels in 378 ER-positive, HER2-negative breast cancer patients by immunohistochemistry using tissue microarray. We found that Beclin 1 was highly expressed in normal mammary gland epithelia. In contrast, it was either not expressed or only moderately expressed in 78.0 % of breast adenocarcinoma tissue. Compared to the subset overexpressing Beclin 1, the subset in which Beclin 1 levels were reduced had a poor 5-year overall survival rate (OS, 85.1 % vs. 94.1 %, P = 0.005) and a poor distant metastasis-free survival (DMFS, 79.1 % vs. 89.3 %, P = 0.037). Cox multivariate analysis confirmed that Beclin 1 was indeed an independent prognostic factor for OS and DMFS. Additionally, Beclin 1 positively correlated with HIF-1α expression (r = 0.206, P < 0.001). Importantly, among patients with HIF-1α overexpression, low levels of Beclin 1 predicted a worse OS. Our study confirmed that deficiency of Beclin 1 was a negative prognostic factor for OS and DMFS in ER-positive, HER2-negative breast cancer. The combination of Beclin 1 and HIF-1α refined the risk definition of the patient subset and provided a novel way to identify those with a high risk of relapse.

Beclin 1 expression is an independent prognostic factor for gastric carcinomas

Beclin 1, an important autophagy-related protein in human cells, is involved in autophagy, differentiation, anti-apoptosis, and cancer progression, which is increased during periods of cell stress and extinguished during the cell cycle. In order to clarify the role of Beclin 1 in gastric carcinogenesis and subsequent progression, its expression was examined by immunohistochemistry and in situ hybridization (ISH) on tissue microarrays containing gastric carcinomas, adjacent non-neoplastic mucosa, and metastatic lymph node. Gastric carcinoma tissue and cell lines were studied for Beclin 1 expression by Western blot or RT-PCR, respectively. The results demonstrated that Beclin 1 was distinctively expressed in GES-1, AGS, BGC-823, GT-3 TKB, HGC-27, KATO-III, MGC-803, MKN28, MKN45, SCH, SGC-7901, or STKM-2 at both mRNA and protein levels. However, Beclin 1 mRNA was highly expressed in gastric carcinoma than matched mucosa by real-time PCR and ISH (P < 0.05). Beclin 1 expression was negatively related to distant metastasis and poor prognosis of gastric carcinoma (P < 0.05). Beclin 1 was highly expressed in male than female patients with gastric carcinoma (P < 0.05). The 65-year-elder patients with gastric carcinoma had higher Beclin 1 expression than the younger ones (P < 0.05). The diffuse-type carcinomas showed less Beclin 1 expression than intestinal- and mixed-type ones (P < 0.05). In intestinal-type gastric carcinoma, Beclin 1 expression was inversely associated with venous invasion, lymph node metastasis, and tumor-node-metastasis (TNM) staging (P < 0.05). Kaplan-Meier analysis indicated that Beclin 1 expression was positively linked to favorable prognosis of the patients with overall and intestinal-type carcinoma (P < 0.05). Cox's proportional hazard model indicated that venous invasion, lymph node metastasis, distant metastasis, TNM staging, and Beclin 1 expression were independent prognostic factors for gastric carcinomas (P < 0.05). It was suggested that aberrant Beclin 1 expression is closely linked to pathogenesis, metastasis, and differentiation of gastric carcinoma. Beclin 1 expression might be employed to indicate the favorable prognosis of gastric carcinomas as an independent factor.

Autophagy and Bcl-2/BNIP3 death regulatory pathway in non-small cell lung carcinomas

We recently showed that non-small cell lung carcinomas (NSCLCs) are of dismal prognosis when encompassing accelerated autophagic activity. The regulation of this abnormally functioning degradation system and its association with hypoxia and apoptosis in lung carcinoma patients is unexplored. In this study we used 115 NSCLC tissues to examine the immunohistochemical expression of four distinct molecules - the major regulator of autophagy Beclin 1, the anti-apoptotic and anti-autophagic protein Bcl-2, the pro-apoptotic and pro-autophagic protein BNIP3, and a marker of hypoxia and glucolysis, the glucose transporter Glut 1. Most cases showed reduced reactivity for Beclin 1 (62%) and Bcl-2 (82%) proteins, almost half of our sample revealed strong BNIP3 expression (57%), whereas most of the carcinomas strongly expressed Glut 1 antigen (71%). Beclin 1 expression showed no association with survival. Bcl-2 positivity was a marker of good prognosis (p = 0.04), whereas BNIP3 (p = 0.0004) and Glut 1 (p = 0.03) expression correlated with poor outcome in Stage I disease. Autophagic status was negatively associated with Bcl-2 (p = 0.0006), but positively with Glut 1 expression (p = 0.001). In conclusion, the accelerated autophagic status in NSCLC is unrelated to Beclin 1 and BNIP3 expression, but does show significant association with Bcl-2 reactivity. Furthermore, we showed important correlations between glucolysis and autophagy, guiding new pathways in future lung carcinoma research.

Autophagy and apoptosis-related genes in chronic liver disease and hepatocellular carcinoma

Background

Dysregulation of autophagy is important in the pathogenesis of many diseases, including cancer. Several aspects of the biological role of autophagy are however still unclear and the relationship between apoptosis and autophagy, particularly in the liver has yet to be thoroughly explored. In this study we evaluated the expression of Beclin 1 (one of the main autophagocytic agents, which bridges autophagy, apoptosis and both differentiation), and both pro- (Bad, Bax) and anti-apoptotic (Bcl-2, Bcl-xL) factors in liver samples from patients with different stages of liver disease.

Methods

The study concerned 93 patients from 49 cases of chronic hepatitis (CH) (30 HCV and 19 HBV-related), 13 of cirrhosis (CIRR) (10 HCV and 3 HBV-related), 21 of hepatocellular carcinoma (both HCC and peritumoral tissues [PHCC]), and 10 controls (CONTR). Real-time PCR and Western blotting were used to measure mRNA and protein expression levels.

Results

Beclin 1 mRNA levels were lower in HCC than in CH (P = 0.010) or CIRR (P = 0.011), and so were the Bcl-xL transcripts (P < 0.0001). Bad mRNA levels were higher in CH and CIRR than in CONTR, while Bax transcripts were increased in all tissues (P = 0.036). PHCC expressed the highest Bcl-2 mRNA levels. HBV-related CH tissues showed significantly higher Bcl-xL and Bad mRNA levels than HCV-related CH (P = 0.003 and P = 0.016, respectively).

Conclusions

High Beclin 1, Bcl-xL and Bad levels in CH and CIRR tissues suggest an interaction between autophagy and apoptosis in the early and intermediate stages of viral hepatitis. In HCC these processes seem to be downregulated, probably enabling the survival and growth of neoplastic hepatocytes.