Clinicopathological significance of BGP expression in non-small-cell lung carcinoma: relationship with histological type, microvessel density and patients' survival

Brain-Type Glycogen Phosphorylase (PYGB) in the Pathologies of Diseases: A Systematic Review

Glycogen metabolism is a form of crucial metabolic reprogramming in cells. PYGB, the brain-type glycogen phosphorylase (GP), serves as the rate-limiting enzyme of glycogen catabolism. Evidence is mounting for the association of PYGB with diverse human diseases. This review covers the advancements in PYGB research across a range of diseases, including cancer, cardiovascular diseases, metabolic diseases, nervous system diseases, and other diseases, providing a succinct overview of how PYGB functions as a critical factor in both physiological and pathological processes. We present the latest progress in PYGB in the diagnosis and treatment of various diseases and discuss the current limitations and future prospects of this novel and promising target.

Inhibition of Glycogen Metabolism Induces Reactive Oxygen Species-Dependent Cytotoxicity in Anaplastic Thyroid Cancer in Female Mice

Anaplastic thyroid cancer (ATC) is one of the most lethal solid tumors, yet there are no effective, long-lasting treatments for ATC patients. Most tumors, including tumors of the endocrine system, exhibit an increased consumption of glucose to fuel cancer progression, and some cancers meet this high glucose requirement by metabolizing glycogen. Our goal was to determine whether ATC cells metabolize glycogen and if this could be exploited for treatment. We detected glycogen synthase and glycogen phosphorylase (PYG) isoforms in normal thyroid and thyroid cancer cell lines and patient-derived biopsy samples. Inhibition of PYG using CP-91,149 induced apoptosis in ATC cells but not normal thyroid cells. CP-91,149 decreased NADPH levels and induced reactive oxygen species accumulation. CP-91,149 severely blunted ATC tumor growth in vivo. Our work establishes glycogen metabolism as a novel metabolic process in thyroid cells, which presents a unique, oncogenic target that could offer an improved clinical outcome.

A Proteomic Platform Unveils the Brain Glycogen Phosphorylase as a Potential Therapeutic Target for Glioblastoma Multiforme

In the last few years, several efforts have been made to identify original strategies against glioblastoma multiforme (GBM): this requires a more detailed investigation of the molecular mechanism of GBM so that novel targets can be identified for new possible therapeutic agents. Here, using a combined biochemical and proteomic approach, we evaluated the ability of a blood–brain barrier-permeable 2,3-benzodiazepin-4-one, called 1g, to interfere with the activity and the expression of brain glycogen phosphorylase (PYGB) on U87MG cell line in parallel with the capability of this compound to inhibit the cell growth and cycle. Thus, our results highlighted PYGB as a potential therapeutic target in GBM prompting 1g as a capable anticancer drug thanks to its ability to negatively modulate the uptake and metabolism of glucose, the so-called “Warburg effect”, whose increase is considered a common feature of cancer cells in respect of their normal counterparts.

Muscle Glycogen Phosphorylase and Its Functional Partners in Health and Disease

Glycogen phosphorylase (PG) is a key enzyme taking part in the first step of glycogenolysis. Muscle glycogen phosphorylase (PYGM) differs from other PG isoforms in expression pattern and biochemical properties. The main role of PYGM is providing sufficient energy for muscle contraction. However, it is expressed in tissues other than muscle, such as the brain, lymphoid tissues, and blood. PYGM is important not only in glycogen metabolism, but also in such diverse processes as the insulin and glucagon signaling pathway, insulin resistance, necroptosis, immune response, and phototransduction. PYGM is implicated in several pathological states, such as muscle glycogen phosphorylase deficiency (McArdle disease), schizophrenia, and cancer. Here we attempt to analyze the available data regarding the protein partners of PYGM to shed light on its possible interactions and functions. We also underline the potential for zebrafish to become a convenient and applicable model to study PYGM functions, especially because of its unique features that can complement data obtained from other approaches.

Glycogen Phosphorylase B Is Regulated by miR101-3p and Promotes Hepatocellular Carcinoma Tumorigenesis

Glycogen metabolism plays a key role in tumorigenesis. High expression levels of glycogen phosphorylase B (PYGB) were reported in several cancers and might be served as a prognostic biomarker for cancer from precancerous lesions. Previous studies indicated the high expression of PYGB in hepatocellular carcinoma (HCC) tissues. However, the detailed roles of PYGB in HCC, as well as the regulatory mechanisms, are still unclear. In this study, we confirmed that PYGB was overexpressed in HCC tissues. PYGB overexpression was significantly associated with an aggressive tumor phenotype and poor prognosis of HCC patients. Functionally, PYGB knockdown suppressed HCC cell proliferation, migration and invasion in vitro, as well as tumorigenesis and metastasis in vivo. Bioinformatics analysis indicated that PYGB overexpression might enhance epithelial to mesenchymal transition (EMT) in HCC. Moreover, miR-101-3p was identified to post-transcriptionally inhibit the expression of PYGB via binding to 3′-UTR of PYGB. Overexpression of PYGB antagonized the regulatory effect of miR-101-3p on cell proliferation, migration and invasion in HCC cells. In summary, our results suggest that miR-101-3p/PYGB axis has an important role in HCC and PYGB could be served as a novel prognostic biomarker and therapeutic target for improving the prognosis of HCC patients.

PYGB facilitates cell proliferation and invasiveness in non-small cell lung cancer by activating the Wnt-β-catenin signaling pathway

Brain-type glycogen phosphorylase (PYGB) has been correlated with the progression of various human malignancies; however, its effects and regulatory mechanisms in non-small cell lung cancer (NSCLC) are still unclear. We used Western blotting, immunohistochemistry, and qRT-PCR to verify that the protein and mRNA expression levels of PYGB are up-regulated in both NSCLC cell lines and tissues. The expression of PYGB was positively related to TNM stage, positive lymph node metastasis, and poor prognosis in patients with NSCLC. Moreover, overexpression of PYGB promoted cell proliferation, migration, and invasiveness, but inhibited apoptosis, in vitro. Immunofluorescence assays showed that overexpression of PYGB promoted the nuclear import and accumulation of β-catenin. By comparison, silencing PYGB produced the opposite effects. Further, overexpression of PYGB resulted in activation of the Wnt signaling pathway, and transfection with Sh-PYGB produced the opposite effect, and these effects were abrogated by XAV-939 (a β-catenin inhibitor) or overexpression of β-catenin, respectively. Finally, knockdown of PYGB inhibited tumor growth in a mouse model of xenograft tumors. These findings highlight the role of PYGB in the progression of NSCLC, and reveal a link between PYGB and the Wnt-β-catenin signaling pathway, thus providing a new potential target for treatment of NSCLC.

Glycogen phosphorylase B promotes ovarian cancer progression via Wnt/β-catenin signaling and is regulated by miR-133a-3p

BACKGROUND

Ovarian cancer is one of the most common gynecologic cancers with high morbidity and mortality in women. Glycogen metabolism plays a critical role in cancer development and glycogen phosphorylase B (PYGB) has reported to be involved in various tumors. Here, we explored the role of PYGB in ovarian cancer.

METHODS

PYGB mRNA expression were examined in ovarian cancer tissue and also analyzed using the dataset from The Cancer Genome Atlas cohort. Correlations between PYGB expression and prognosis of ovarian cancer patients were analyzed. PYGB was silenced to evaluate the ovarian cell proliferation, invasion and migration in vitro and tumorigenesis in vivo. MiR-133a-3p targeting PYGB was identified using online tools and confirmed with luciferase reporter experiment. MiR-133a-3p overexpression using miRNA mimics was conducted to evaluate its function on ovarian cancer cells.

RESULTS

We showed that PYGB was upregulated in ovarian cancer tissue and high level of PYGB expression is markedly correlated with poor prognosis of ovarian cancer patients. PYGB knockdown significantly suppressed ovarian cancer cell proliferation, invasion and migration. Xenograft tumor formation further demonstrated that knockdown PYGB inhibited ovarian tumor development. Bioinformatics analysis revealed that PYGB regulated Wnt/β-catenin signaling pathway in ovarian cancer cells. Mechanistically, miR-133a-3p directly bound to 3'-untranslated region of PYGB and overexpression miR-133a-3p suppressed proliferation, invasion and migration in ovarian cancer cells.

CONCLUSION

Our data suggest that miR-133a-3p/PYGB/Wnt-β-catenin axis plays a critical role in human ovarian cancer, which might serve as a promising therapeutic target of ovarian cancer treatment in the future.

Silencing of PYGB suppresses growth and promotes the apoptosis of prostate cancer cells via the NF‑κB/Nrf2 signaling pathway

Brain‑type glycogen phosphorylase (PYGB) is an enzyme that metabolizes glycogen, whose function is to provide energy for an organism in an emergency state. The present study purposed to investigate the role and mechanism of PYGB silencing on the growth and apoptosis of prostate cancer cells. A cell counting kit‑8 assay and flow cytometry were performed to determine the cell viability, apoptosis and reactive oxygen species (ROS) content, respectively. Colorimetry was performed to analyze the activity of caspase‑3. Western blotting and reverse transcription‑quantitative polymerase chain reaction were used to evaluate the associated mRNA and protein expression levels. The results revealed that PYGB was upregulated in prostate cancer tissues and was associated with disease progression. In addition, PYGB silencing suppressed the cell viability of PC3 cells. PYGB silencing promoted apoptosis of PC3 cells via the regulation of the expression levels of cleaved‑poly (adenosine diphosphate‑ribose) polymerase, cleaved‑caspase‑3, B‑cell lymphoma‑2 (Bcl‑2) and Bcl‑2‑associated X protein. PYGB silencing increased the ROS content in PC3 cells, and affected nuclear factor (NF)‑κB/nuclear factor‑erythroid 2‑related factor 2 (Nrf2) signaling pathways in PC3 cells. In conclusion, PYGB silencing suppressed the growth and promoted the apoptosis of prostate cancer cells by affecting the NF‑κB/Nrf2 signaling pathway. The present study provided evidence that may lead to the development of a potential therapeutic strategy for prostate cancer.

Quantitative proteomic analysis of human lung tumor xenografts treated with the ectopic ATP synthase inhibitor citreoviridin

ATP synthase is present on the plasma membrane of several types of cancer cells. Citreoviridin, an ATP synthase inhibitor, selectively suppresses the proliferation and growth of lung cancer without affecting normal cells. However, the global effects of targeting ectopic ATP synthase in vivo have not been well defined. In this study, we performed quantitative proteomic analysis using isobaric tags for relative and absolute quantitation (iTRAQ) and provided a comprehensive insight into the complicated regulation by citreoviridin in a lung cancer xenograft model. With high reproducibility of the quantitation, we obtained quantitative proteomic profiling with 2,659 proteins identified. Bioinformatics analysis of the 141 differentially expressed proteins selected by their relative abundance revealed that citreoviridin induces alterations in the expression of glucose metabolism-related enzymes in lung cancer. The up-regulation of enzymes involved in gluconeogenesis and storage of glucose indicated that citreoviridin may reduce the glycolytic intermediates for macromolecule synthesis and inhibit cell proliferation. Using comprehensive proteomics, the results identify metabolic aspects that help explain the antitumorigenic effect of citreoviridin in lung cancer, which may lead to a better understanding of the links between metabolism and tumorigenesis in cancer therapy.

Clinical and experimental studies regarding the expression and diagnostic value of carcinoembryonic antigen-related cell adhesion molecule 1 in non-small-cell lung cancer

Background

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is a multifunctional Ig-like cell adhesion molecule that has a wide range of biological functions. According to previous reports, serum CEACAM1 is dysregulated in different malignant tumours and associated with tumour progression. However, the serum CEACAM1 expression in non-small-cell lung carcinomas (NSCLC) is unclear. The different expression ratio of CEACAM1-S and CEACAM1-L isoform has seldom been investigated in NSCLC. This research is intended to study the serum CEACAM1 and the ratio of CEACAM1-S/L isoforms in NSCLC.

Methods

The expression of the serum CEACAM1 was determined by enzyme-linked immunosorbent assay. The protein expression and the location of CEACAM1 in tumours were observed by immunohistochemical staining. The CEACAM1 mRNA levels in tumour and normal adjacent tissues were measured using quantitative real-time PCR, and the expression patterns and the rate of CEACAM1-S and CEACAM1-L were analysed by reverse transcription-PCR.

Results

Serum CEACAM1 levels were significantly higher in NSCLC patients compared with that from normal healthy controls (P <0.0001). 17 patients (81%) among 21 showed high expression of CEACAM1 by immunohistochemical staining. Although no significant differences were found between tumour and normal tissues on mRNA expression levels of CEACAM1 (P >0.05), the CEACAM1-S and the CEACAM1-S/L (S: L) ratios were significantly higher in tumour than normal tissues (P <0.05).

Conclusions

Our data indicated that the serum levels of CEACAM1 could discriminate lung cancer patients from health donors and that CEACAM1 might be a useful marker in early diagnosis of NSCLC. Moreover, our results showed that the expression patterns of CEACAM1 isoforms could be changed during oncogenesis, even when total CEACAM1 in tumour tissues did not show significant changes. Our study suggested that the expression ratios of CEACAM1-S/CEACAM1-L might be a better diagnostic indicator in NSCLC than the quantitative changes of CEACAM1.

Identification and differential expression of human carcinoma-associated antigens in hepatocellular carcinoma tissues

This study was designed to identify and verify hepatocellular carcinoma (HCC)-associated human carcinoma antigens (HCAs) that may be useful as tumor markers for HCC. We found that BCE075 and BCD021 anti-HCA antibodies were immunostained in the liver tissue samples and showed specific staining. Their expression was increased in HCC compared with normal liver tissues (P = 0.008). Immunoprecipitation and mass spectrometry analyses of the proteins precipitated by these two antibodies were identified to be cytoskeleton-associated protein 4 (CLIMP63) and brain-type glycogen phosphorylase (PYGB). This study demonstrated that HCC tissues expressed specific HCA glycoproteins, suggesting that our mouse monoclonal anti-HCA antibodies could be useful for immunohistochemical analysis of HCA expression as potential biomarkers for HCC diagnosis.

TC-VGC: a tumor classification system using variations in genes' correlation

Classification analysis of microarray data is widely used to reveal biological features and to diagnose various diseases, including cancers. Most existing approaches improve the performance of learning models by removing most irrelevant and redundant genes from the data. They select the marker genes which are expressed differently in normal and tumor tissues. These techniques ignore the importance of the complex functional-dependencies between genes. In this paper, we propose a new method for cancer classification which uses distinguished variations of gene-gene correlation in two sample groups. The cancer specific genetic network composed of these gene pairs contains many literature-curated prostate cancer genes, and we were successful in identifying new candidate prostate cancer genes inferred by them. Furthermore, this method achieved a high accuracy with a small number of genes in cancer classification.

Enzymatic features of the glucose metabolism in tumor cells

Many tumor types exhibit an impaired Pasteur effect, i.e. despite the presence of oxygen, glucose is consumed at an extraordinarily high rate compared with the tissue from which they originate - the so-called 'Warburg effect'. Glucose has to serve as the source for a diverse array of cellular functions, including energy production, synthesis of nucleotides and lipids, membrane synthesis and generation of redox equivalents for antioxidative defense. Tumor cells acquire specific enzyme-regulatory mechanisms to direct the main flux of glucose carbons to those pathways most urgently required under challenging external conditions such as varying substrate availability, presence of anti-cancer drugs or different phases of the cell cycle. In this review we summarize the currently available information on tumor-specific expression, activity and kinetic properties of enzymes involved in the main pathways of glucose metabolism with due regard to the explanation of the regulatory basis and physiological significance of the Warburg effect. We conclude that, besides the expression level of the metabolic enzymes involved in the glucose metabolism of tumor cells, the unique tumor-specific pattern of isozymes and accompanying changes in the metabolic regulation below the translation level enable tumor cells to drain selfishly the blood glucose pool that non-transformed cells use as sparingly as possible.

Development of a novel splice array platform and its application in the identification of alternative splice variants in lung cancer

Background

Microarrays strategies, which allow for the characterization of thousands of alternative splice forms in a single test, can be applied to identify differential alternative splicing events. In this study, a novel splice array approach was developed, including the design of a high-density oligonucleotide array, a labeling procedure, and an algorithm to identify splice events.

Results

The array consisted of exon probes and thermodynamically balanced junction probes. Suboptimal probes were tagged and considered in the final analysis. An unbiased labeling protocol was developed using random primers. The algorithm used to distinguish changes in expression from changes in splicing was calibrated using internal non-spliced control sequences. The performance of this splice array was validated with artificial constructs for CDC6, VEGF, and PCBP4 isoforms. The platform was then applied to the analysis of differential splice forms in lung cancer samples compared to matched normal lung tissue. Overexpression of splice isoforms was identified for genes encoding CEACAM1, FHL-1, MLPH, and SUSD2. None of these splicing isoforms had been previously associated with lung cancer.

Conclusions

This methodology enables the detection of alternative splicing events in complex biological samples, providing a powerful tool to identify novel diagnostic and prognostic biomarkers for cancer and other pathologies.