LY6E: a conductor of malignant tumor growth through modulation of the PTEN/PI3K/Akt/HIF-1 axis

Leveraging a disulfidptosis-based signature to characterize heterogeneity and optimize treatment in multiple myeloma

Background

Disulfidptosis is an emerging type of programmed cell death related to ROS accumulation and aberrant disulfide bond formation. Multiple myeloma (MM) is the second most prevalent hematologic malignancy characterized by a high synthesis rate of disulfide bond-rich proteins and chronic oxidative stress. However, the relationship between disulfidptosis and MM is still unclear.

Methods

Using the non-negative matrix factorization and lasso algorithm, we constructed the disulfidptosis-associated subtypes and the prognostic model on the GEO dataset. We further explored genetic mutation mapping, protein-protein interactions, functional enrichment, drug sensitivity, drug prediction, and immune infiltration analysis among subtypes and risk subgroups. To improve the clinical benefits, we combined risk scores and clinical metrics to build a nomogram. Finally, in vitro experiments examined the expression patterns of disulfidptosis-related genes (DRGs) in MM.

Results

By cluster analysis, we obtained three subtypes with C2 having a worse prognosis than C3. Consistently, C2 exhibited significantly lower sensitivity to doxorubicin and lenalidomide, as well as a higher propensity for T-cell depletion and a non-responsive state to immunotherapy. Similarly, in the subsequent prognostic model, the high-scoring group had a worse prognosis and a higher probability of T-cell dysfunction, immunotherapy resistance, and cancer cell self-renewal. DRGs and risk genes were widely mutated in cancers. Subtypes and risk subgroups differed in ROS metabolism and the p53 signaling pathway. We further identified eight genes differentially expressed in risk subgroups as drug targets against MM. Then 27 drugs targeting the high-risk group were predicted. Based on the DRGs and risk genes, we constructed the miRNA and TF regulatory networks. The nomogram of combined ISS, age, and risk score showed good predictive performance. qRT-PCR of cell lines and clinical specimens provided further support for prognostic modeling.

Conclusion

Our research reveals the prognostic value of disulfidptosis in MM and provides new perspectives for identifying heterogeneity and therapeutic targets.

LY6E as a new prognostic biomarker of multiple myeloma-related bone disease

Osteolytic bone disease, which deteriorates the quality of life, is a prevalent complication of multiple myeloma (MM). In this study, we utilized bioinformatics analysis to identify the differentially expressed genes (DEGs) associated with MM bone disease (MBD) from the Gene Expression Omnibus (GEO) databases. Here, the Kaplan-Meier (K-M) curve and Cox regression analyses demonstrated that the key molecule lymphocyte antigen 6 complex (LY6E) was closely correlated with the MM progression, unfavorable prognosis and the formation of MBD. Furthermore, we confirmed that higher LY6E expression promoted MM cell proliferation and osteoclast differentiation in vitro. Taken together, these findings may illuminate the theoretical foundation for LY6E in MBD formation and identify it as a neoteric therapeutic target for MM.

ZBTB7A forms a heterodimer with ZBTB2 and inhibits ZBTB2 homodimerization required for full activation of HIF-1

Hypoxia-inducible factor 1 (HIF-1), recognized as a master transcription factor for adaptation to hypoxia, is associated with malignant characteristics and therapy resistance in cancers. It has become clear that cofactors such as ZBTB2 are critical for the full activation of HIF-1; however, the mechanisms downregulating the ZBTB2-HIF-1 axis remain poorly understood. In this study, we identified ZBTB7A as a negative regulator of ZBTB2 by analyzing protein sequences and structures. We found that ZBTB7A forms a heterodimer with ZBTB2, inhibits ZBTB2 homodimerization necessary for the full expression of ZBTB2-HIF-1 downstream genes, and ultimately delays the proliferation of cancer cells under hypoxic conditions. The Cancer Genome Atlas (TCGA) analyses revealed that overall survival is better in patients with high ZBTB7A expression in their tumor tissues. These findings highlight the potential of targeting the ZBTB7A-ZBTB2 interaction as a novel therapeutic strategy to inhibit HIF-1 activity and improve treatment outcomes in hypoxia-related cancers.

Ly6E on tumor cells impairs anti-tumor T-cell responses: a novel mechanism of tumor-induced immune exclusion

BACKGROUND

Lymphocyte antigen 6 complex, locus E (Ly6E) has been initially demonstrated to involve in T cell activity and impair viral infectivity. Recently, high expression levels of Ly6E have been reported in tumor microenvironment (TME) of various types of cancers. However, the immunoregulatory mechanism of Ly6E manipulating TME remains unknown.

METHODS

TCGA database and Kaplan-Meier plotter database were used to evaluate the correlation between Ly6E expression levels and cancer patient survival. After analyzing Ly6E expression levels in human breast cancer tissues and tumor cell lines, we generated Ly6E knockout (KO) and overexpression (OE) mouse cell lines. Cell proliferation ability in vitro and the ability of growth and metastasis in mouse tumor models were compared between KO/OE and wild-type tumor cells. On day 7 after tumor implantation, tumor tissues were separated for flow cytometric assay, bulk RNA sequencing and single-cell RNA sequencing (ScRNA-seq). The role of Ly6E-expressing tumor cell on macrophage was analyzed in vitro.

RESULTS

Our result surprisingly found that high Ly6E expression levels were associated with CD8+ T cell exclusion in tumor tissues and resistance to immunotherapy. Our data showed that knockout of Ly6E in tumor cells prompts tumor regression and inhibits tumor metastases, and Ly6E-OE tumor cells vice versa. The enhanced anti-tumor effect of Ly6E knockout in tumor cells was dependent on T cell response and formed long-lasting memory. The increase in the CD8+ T-cell infiltration into the tumor islet of Ly6E-KO tumors confirmed the role of Ly6E on T cell exclusion. ScRNA-seq analysis showed that M2 macrophages are particularly abundant in the Ly6E-expressing tumor tissues, especially M2-4 macrophage cluster identified by high levels of Arg-1, indicates that Ly6E-expressing tumor cells might restrict T cell infiltration via M2 macrophages. Moreover, in vitro assay showed that cell culture media derived from Ly6E-positive tumor cells promoted macrophage migration and M2 polarization.

CONCLUSION

Our study illuminated that Ly6E-expressing tumor cells facilitated the accumulation of M2 macrophages in TME, which contributes to CD8+ T cell exclusion and provides new insights for improving efficacy of cancer immunotherapy.

Hypovascular insulinoma with reduced microvessel density on histopathology: a case report

Pancreatic neuroendocrine tumors (PanNETs) are generally hypervascular and readily detectable on imaging tests. However, hypovascular PanNETs are clinically problematic, requiring multiple imaging tests and tissue analyses to differentiate them from pancreatic ductal cancers. A 41 year-old man presented with Whipple's triad; 72 h fasting test followed by glucagon challenge test suggested insulinoma. However, contrast-enhanced computed tomography image showed a 17 mm tumor with poor enhancement and unclear borders in the tail of the pancreas. Abdominal magnetic resonance imaging and contrast-enhanced endoscopic ultrasonography (EUS) indicated cystic degeneration and necrosis at the same site; EUS-guided fine-needle aspiration cytology indicated a PanNET Grade 1 tumor. Although the imaging was inconclusive, diazoxide treatment ameliorated the hypoglycemia-related symptoms and insulinoma was deemed likely; following tail pancreatectomy and splenectomy, the symptoms disappeared. Pathological examination revealed a tumor positive for insulin and classed as PanNET Grade 1 according to the 2019 WHO classification. The microvessel density (MVD) of the tumor was found to be as low as 3.9%, which may partly account for the inconclusive images. The present case was difficult to diagnose preoperatively due to hypovascularity on imaging because of reduced MVD. It is clinically important to evaluate MVD in cases of hypovascular PanNETs by multiple preoperative imaging studies to differentiate them from pancreatic cancers and to validate the findings by postoperative pathological analysis.

Lymphocyte antigen 6 family member E suppresses apoptosis and promotes pancreatic cancer growth and migration via Wnt/β-catenin pathway activation

Pancreatic cancer (PC) is the primary cause of cancer-related mortality. Due to the absence of reliable biomarkers for predicting prognosis or guiding treatment, there is an urgent need for molecular studies on PC. Lymphocyte antigen 6 family member E (LY6E) is implicated in uncontrolled cell growth across various cancers. However, the precise mechanism of LY6E in PC remains unclear. Here, we conducted comprehensive bioinformatic analyses using online tools and R- × 64-4.1.1, complemented by experimental validation through Western blotting, immunohistochemistry, immunosorbent assays, flow cytometry, cell assays, and animal models. Our findings reveal significantly elevated expression of LY6E in PC, correlating with poor prognosis. LY6E knockdown inhibited proliferation, invasion, and migration of PC cells, while enhancing apoptosis evidenced by increased cleaved caspase 3 levels and alterations in the Bcl-2/Bax ratio. Conversely, LY6E overexpression promoted PC cell proliferation and migration, and inhibited apoptosis. Mechanistically, LY6E downregulation suppressed the Wnt/β-catenin signaling pathway. In vivo studies demonstrated that LY6E suppression attenuated tumor growth in murine models. Additionally, LY6E suppression resulted in reduced tumor growth in mice. In conclusion, our study confirms the significant role of LY6E in the progression of PC. LY6E, serving as an independent prognostic indicator, has the potential to serve as a valuable biomarker for PC to inform treatment strategies.

Inflammatory Alterations to Renal Lymphatic Endothelial Cell Gene Expression in Mouse Models of Hypertension

INTRODUCTION

Hypertension (HTN) is a major cardiovascular disease that can cause and be worsened by renal damage and inflammation. We previously reported that renal lymphatic endothelial cells (LECs) increase in response to HTN and that augmenting lymphangiogenesis in the kidneys reduces blood pressure and renal pro-inflammatory immune cells in mice with various forms of HTN. Our aim was to evaluate the specific changes that renal LECs undergo in HTN.

METHODS

We performed single-cell RNA sequencing. Using the angiotensin II-induced and salt-sensitive mouse models of HTN, we isolated renal CD31+ and podoplanin+ cells.

RESULTS

Sequencing of these cells revealed three distinct cell types with unique expression profiles, including LECs. The number and transcriptional diversity of LECs increased in samples from mice with HTN, as demonstrated by 597 differentially expressed genes (p < 0.01), 274 significantly enriched pathways (p < 0.01), and 331 regulons with specific enrichment in HTN LECs. These changes demonstrate a profound inflammatory response in renal LECs in HTN, leading to an increase in genes and pathways associated with inflammation-driven growth and immune checkpoint activity in LECs.

CONCLUSION

These results reinforce and help to further explain the benefits of renal LECs and lymphangiogenesis in HTN.

Exploring the Potential of Antibody-Drug Conjugates in Targeting Non-small Cell Lung Cancer Biomarkers

Antibody-drug conjugates (ADCs), combining the cytotoxicity of the drug payload with the specificity of monoclonal antibodies, are one of the rapidly evolving classes of anti-cancer agents. These agents have been successfully incorporated into the treatment paradigm of many malignancies, including non-small cell lung cancer (NSCLC). The NSCLC is the most prevalent subtype of lung cancer, having a considerable burden on the cancer-related mortality and morbidity rates globally. Several ADC molecules are currently approved by the Food and Drug Administration (FDA) to be used in patients with NSCLC. However, the successful management of NSCLC patients using these agents was met with several challenges, including the development of resistance and toxicities. These shortcomings resulted in the exploration of novel therapeutic targets that can be targeted by the ADCs. This review aims to explore the recently identified ADC targets along with their oncologic mechanisms. The ADC molecules targeting these biomarkers are further discussed along with the evidence from clinical trials.

Hypoxia-Inducible Factor-Dependent and Independent Mechanisms Underlying Chemoresistance of Hypoxic Cancer Cells

In hypoxic regions of malignant solid tumors, cancer cells acquire resistance to conventional therapies, such as chemotherapy and radiotherapy, causing poor prognosis in patients with cancer. It is widely recognized that some of the key genes behind this are hypoxia-inducible transcription factors, e.g., hypoxia-inducible factor 1 (HIF-1). Since HIF-1 activity is suppressed by two representative 2-oxoglutarate-dependent dioxygenases (2-OGDDs), PHDs (prolyl-4-hydroxylases), and FIH-1 (factor inhibiting hypoxia-inducible factor 1), the inactivation of 2-OGDD has been associated with cancer therapy resistance by the activation of HIF-1. Recent studies have also revealed the importance of hypoxia-responsive mechanisms independent of HIF-1 and its isoforms (collectively, HIFs). In this article, we collate the accumulated knowledge of HIF-1-dependent and independent mechanisms responsible for resistance of hypoxic cancer cells to anticancer drugs and briefly discuss the interplay between hypoxia responses, like EMT and UPR, and chemoresistance. In addition, we introduce a novel HIF-independent mechanism, which is epigenetically mediated by an acetylated histone reader protein, ATAD2, which we recently clarified.

Integrative Bioinformatics-Gene Network Approach Reveals Linkage between Estrogenic Endocrine Disruptors and Vascular Remodeling in Peripheral Arterial Disease

Vascular diseases, including peripheral arterial disease (PAD), pulmonary arterial hypertension, and atherosclerosis, significantly impact global health due to their intricate relationship with vascular remodeling. This process, characterized by structural alterations in resistance vessels, is a hallmark of heightened vascular resistance seen in these disorders. The influence of environmental estrogenic endocrine disruptors (EEDs) on the vasculature suggests a potential exacerbation of these alterations. Our study employs an integrative approach, combining data mining with bioinformatics, to unravel the interactions between EEDs and vascular remodeling genes in the context of PAD. We explore the molecular dynamics by which EED exposure may alter vascular function in PAD patients. The investigation highlights the profound effect of EEDs on pivotal genes such as ID3, LY6E, FOS, PTP4A1, NAMPT, GADD45A, PDGF-BB, and NFKB, all of which play significant roles in PAD pathophysiology. The insights gained from our study enhance the understanding of genomic alterations induced by EEDs in vascular remodeling processes. Such knowledge is invaluable for developing strategies to prevent and manage vascular diseases, potentially mitigating the impact of harmful environmental pollutants like EEDs on conditions such as PAD.

Molecular Mechanisms of Neuroprotection after the Intermittent Exposures of Hypercapnic Hypoxia

The review introduces the stages of formation and experimental confirmation of the hypothesis regarding the mutual potentiation of neuroprotective effects of hypoxia and hypercapnia during their combined influence (hypercapnic hypoxia). The main focus is on the mechanisms and signaling pathways involved in the formation of ischemic tolerance in the brain during intermittent hypercapnic hypoxia. Importantly, the combined effect of hypoxia and hypercapnia exerts a more pronounced neuroprotective effect compared to their separate application. Some signaling systems are associated with the predominance of the hypoxic stimulus (HIF-1α, A1 receptors), while others (NF-κB, antioxidant activity, inhibition of apoptosis, maintenance of selective blood-brain barrier permeability) are mainly modulated by hypercapnia. Most of the molecular and cellular mechanisms involved in the formation of brain tolerance to ischemia are due to the contribution of both excess carbon dioxide and oxygen deficiency (ATP-dependent potassium channels, chaperones, endoplasmic reticulum stress, mitochondrial metabolism reprogramming). Overall, experimental studies indicate the dominance of hypercapnia in the neuroprotective effect of its combined action with hypoxia. Recent clinical studies have demonstrated the effectiveness of hypercapnic-hypoxic training in the treatment of childhood cerebral palsy and diabetic polyneuropathy in children. Combining hypercapnic hypoxia with pharmacological modulators of neuro/cardio/cytoprotection signaling pathways is likely to be promising for translating experimental research into clinical medicine.

DDX5 enhances HIF-1 activity by promoting the interaction of HIF-1α with HIF-1β and recruiting the resulting heterodimer to its target gene loci

BACKGROUND INFORMATION

Cancer cells acquire malignant characteristics and therapy resistance by employing the hypoxia-inducible factor 1 (HIF-1)-dependent adaptive response to hypoxic microenvironment in solid tumors. Since the underlying molecular mechanisms remain unclear, difficulties are associated with establishing effective therapeutic strategies.

RESULTS

We herein identified DEAD-box helicase 5 (DDX5) as a novel activator of HIF-1 and found that it enhanced the heterodimer formation of HIF-1α and HIF-1β and facilitated the recruitment of the resulting HIF-1 to its recognition sequence, hypoxia-response element (HRE), leading to the expression of a subset of cancer-related genes under hypoxia.

CONCLUSIONS

This study reveals that the regulation of HIF-1 recruitment to HRE is an important regulatory step in the control of HIF-1 activity.

SIGNIFICANCE

The present study provides novel insights for the development of strategies to inhibit the HIF-1-dependent expression of cancer-related genes.

Functional Annotation and Gene Set Analysis of Gastric Cancer Risk Loci in a Korean Population

PURPOSE

We aimed to identify the associated single nucleotide polymorphisms (SNPs) with gastric cancer (GC) risk by genome-wide association study (GWAS) and to explore the pathway enrichment of implicated genes and gene-sets with expression patterns.

MATERIALS AND METHODS

The study population was comprised of 1,253 GC cases and 4,827 controls from National Cancer Center and an urban community of the Korean Genome Epidemiology Study and their genotyping was performed. SNPs were annotated, and mapped to genes to prioritize by three mapping approaches by functional mapping and annotation (FUMA). The gene-based analysis and gene-set analysis were conducted with full GWAS summary data using MAGMA. Gene-set pathway enrichment test with those prioritized genes were performed.

RESULTS

In GWAS, rs2303771, a nonsynonymous variant of KLHDC4 gene was top SNP associated significantly with GC (odds ratio, 2.59; p=1.32×10-83). In post-GWAS, 71 genes were prioritized. In gene-based GWAS, seven genes were under significant p < 3.80×10-6 (0.05/13,114); DEFB108B had the lowest p=5.94×10-15, followed by FAM86C1 (p=1.74×10-14), PSCA (p=1.81×10-14), and KLHDC4 (p=5.00×10-10). In gene prioritizing, KLDHC4 was the only gene mapped with all three gene-mapping approaches. In pathway enrichment test with prioritized genes, FOLR2, PSCA, LY6K, LYPD2, and LY6E showed strong enrichment related to cellular component of membrane; a post-translation modification by synthesis of glycosylphosphatidylinositol (GPI)-anchored proteins pathway.

CONCLUSION

While 37 SNPs were significantly associated with the risk of GC, genes involved in signaling pathways related to purine metabolism and GPI-anchored protein in cell membrane are pinpointed to be playing important role in GC.

A LY6E-PHB1-TRIM21 assembly degrades CD14 protein to mitigate LPS-induced inflammatory response

A major theme of host against invading pathogens lies in multiple regulatory nodes that ensure sufficient signals for protection while avoiding excessive signals toward over-inflammation. The TLR4/MD-2/CD14 complex receptor-mediated response to bacterial lipopolysaccharide (LPS) represents a paradigm for understanding the proper control of anti-pathogen innate immunity. In this study, we studied the mechanism by which the glycosylphosphatidylinositol (GPI)-linked LY6E protein constrains LPS response via downregulating CD14. We first showed that LY6E downregulated CD14 via ubiquitin-dependent proteasomal degradation. The subsequent profiling of LY6E protein interactome led to the revelation that the degradation of CD14 by LY6E requires PHB1, which interacts with CD14 in a LY6E-dependent manner. Finally, we identified the PHB1-interacting TRIM21 as the major ubiquitin E3 ligase for the LY6E-mediated ubiquitination of CD14. Together, our study elucidated the molecular basis of LY6E-mediated governance of LPS response, alongside providing new insights to regulatory mechanisms controlling the homeostasis of membrane proteins.

Risk prediction for dermatomyositis-associated hepatocellular carcinoma

OBJECTIVE

To explore dermatomyositis signature genes as potential biomarkers of hepatocellular carcinoma and their associated molecular regulatory mechanisms.

METHODS

Based on the mRNA-Seq data of dermatomyositis and hepatocellular carcinoma in public databases, five dermatomyositis signature genes were screened by LASSO regression analysis and support vector machine (SVM) algorithm, and their biological functions in dermatomyositis with hepatocellular carcinoma were investigated, and a nomogram risk prediction model for hepatocellular carcinoma was constructed and its predictive efficiency was initially evaluated. The immune profile in hepatocellular carcinoma was examined based on the CIBERSORT and ssGSEA algorithms, and the correlation between five dermatomyositis signature genes and tumor immune cell infiltration and immune checkpoints in hepatocellular carcinoma was investigated.

RESULTS

The expression levels of five dermatomyositis signature genes were significantly altered in hepatocellular carcinoma and showed good diagnostic efficacy for hepatocellular carcinoma, suggesting that they may be potential predictive targets for hepatocellular carcinoma, and the risk prediction model based on five dermatomyositis signature genes showed good risk prediction efficacy for hepatocellular carcinoma and has good potential for clinical application. In addition, we also found that the upregulation of SPP1 expression may activate the PI3K/ART signaling pathway through integrin-mediated activation, which in turn regulates the development and progression of hepatocellular carcinoma.

CONCLUSION

LY6E, IFITM1, GADD45A, MT1M, and SPP1 are potential predictive targets for new-onset hepatocellular carcinoma in patients with dermatomyositis, and the upregulation of SPP1 expression may activate the PI3K/ART signaling pathway through the mediation of integrins to promote the development and progression of hepatocellular carcinoma.

Genomic and Transcriptomic Analyses of NF1-Mutant Melanoma Identify Potential Targeted Approach for Treatment

There is currently no targeted therapy to treat NF1-mutant melanomas. In this study, we compared the genomic and transcriptomic signatures of NF1-mutant and NF1 wild-type melanoma to reveal potential treatment targets for this subset of patients. Genomic alterations were verified using qPCR, and differentially expressed genes were independently validated using The Cancer Genome Atlas data and immunohistochemistry. Digital spatial profiling with multiplex immunohistochemistry and immunofluorescence were used to validate the signatures. The efficacy of combinational regimens driven by these signatures was tested through in vitro assays using low-passage cell lines. Pathogenic NF1 mutations were identified in 27% of cases. NF1-mutant melanoma expressed higher proliferative markers MK167 and CDC20 than NF1 wild-type (P = 0.008), which was independently validated both in The Cancer Genome Atlas dataset (P = 0.01, P = 0.03) and with immunohistochemistry (P = 0.013, P = 0.036), respectively. Digital spatial profiling analysis showed upregulation of LY6E within the tumor cells (false discovery rate < 0.01, log2 fold change > 1), confirmed with multiplex immunofluorescence showing colocalization of LY6E in melanoma cells. The combination of MAPK/extracellular signal‒regulated kinase kinase and CDC20 coinhibition induced both cytotoxic and cytostatic effects, decreasing CDC20 expression in multiple NF1-mutant cell lines. In conclusion, NF1-mutant melanoma is associated with a distinct genomic and transcriptomic profile. Our data support investigating CDC20 inhibition with MAPK pathway inhibitors as a targeted regimen in this melanoma subtype.

ZBTB2 links p53 deficiency to HIF-1-mediated hypoxia signaling to promote cancer aggressiveness

Aberrant activation of the hypoxia-inducible transcription factor HIF-1 and dysfunction of the tumor suppressor p53 have been reported to induce malignant phenotypes and therapy resistance of cancers. However, their mechanistic and functional relationship remains largely unknown. Here, we reveal a mechanism by which p53 deficiency triggers the activation of HIF-1-dependent hypoxia signaling and identify zinc finger and BTB domain-containing protein 2 (ZBTB2) as an important mediator. ZBTB2 forms homodimers via its N-terminus region and increases the transactivation activity of HIF-1 only when functional p53 is absent. The ZBTB2 homodimer facilitates invasion, distant metastasis, and growth of p53-deficient, but not p53-proficient, cancers. The intratumoral expression levels of ZBTB2 are associated with poor prognosis in lung cancer patients. ZBTB2 N-terminus-mimetic polypeptides competitively inhibit ZBTB2 homodimerization and significantly suppress the ZBTB2-HIF-1 axis, leading to antitumor effects. Our data reveal an important link between aberrant activation of hypoxia signaling and loss of a tumor suppressor and provide a rationale for targeting a key mediator, ZBTB2, to suppress cancer aggressiveness.

Multidimension Analysis of the Prognostic Value, Immune Regulatory Function, and ceRNA Network of LY6E in Individuals with Colorectal Cancer

BACKGROUND

Lymphocyte antigen 6 complex, locus E (LY6E) is abnormally expressed in several cancers and is associated with poor outcomes. However, the biological role of LY6E in colorectal cancer (CRC) remains largely unknown. Hence, we aimed to evaluate the expression levels, prognostic value, biological functions, and immune effects of LY6E via pan-cancer and CRC analyses using multiple databases.

METHODS

We analyzed the expression pattern of LY6E in various cancers. The prognostic value of LY6E expression was identified using the Kaplan-Meier analysis and the Cox regression models. We used gene set enrichment analysis (GSEA) to identify the potential functions of LY6E. Correlations between the LY6E expression and various factors, including LY6E methylation level, copy number variation (CNV), microsatellite instability (MSI), and immune checkpoint genes, were also analyzed. The levels of LY6E expression and immune infiltration were analyzed using CIBERSORT. We constructed a regulatory network that was in compliance with the competing endogenous RNA (ceRNA) hypothesis. A ceRNA expression-based nomogram was established. Real-time PCR (qRT-PCR) was applied to validate the expression of LY6E-related ceRNA in CRC cell lines.

RESULTS

LY6E is overexpressed in several tumor types, including CRC, and patients with high expression levels of LY6E have a poor prognosis. The Kaplan-Meier analysis and Cox regression analysis showed that LY6E could be considered a favorable prognostic factor in TCGA and GEO cohort. The results of GSEA showed that high LY6E expression levels were associated with immune-related pathways, such as those involved in antigen processing and presentation and the intestinal immune network for IgA production. Six methylation sites of LY6E that were associated with prognostic survival were screened. Moreover, the high levels of LY6E expression were correlated with copy number gain, microsatellite instability high, and immunotherapy response. The results of CIBERSORT analysis demonstrated that the LY6E expression levels were correlated with the infiltration of multiple immune cells, especially T cells. Then, we constructed a ceRNA network (LINC00963/miR-92a-3p/LY6E) and validated it using qRT-PCR. A predictive ceRNA-based nomogram was established and validated.

CONCLUSION

The oncogenic LY6E may serve as a promising marker for the diagnosis and treatment of CRC.

FAM46C as a Potential Marker for Pan-Cancer Prognosis and Predicting Immunotherapeutic Efficacy

Background:FAM46C is a common mutated gene in tumours. A comprehensive understanding of the relationship between FAM46C expression and pan-cancer can guide clinical prognosis and broaden the immunotherapeutic targets.

Methods: Data from The Cancer Genome Atlas and Genotype-Tissue Expression (GTEx) databases were obtained, and gene expression of different tumour types and stages was analysed. Immunohistochemical analysis was performed to detect differences in the FAM46C protein levels in normal and cancerous tissues. The genetic variation of FAM46C was characterised using cBioPortal. The clinical prognostic value of FAM46C and the impact of FAM46C expression levels on the prognosis of patients with different types of cancer were assessed based on Kaplan–Meier and Cox regression analyses. Gene set enrichment analysis (GSEA) was used to analyse the pathways associated with FAM46C. Correlations between FAM46C expression levels and immune infiltration were assessed using the TIMER2 database and CIBERSORT algorithm, and correlations between FAM46C expression and the ESTIMATE, immune and stromal scores were analysed using the ESTIMATE algorithm. In addition, we also analysed the correlation between FAM46C expression and immune activation, suppression genes and immune chemokines.

Results: The expression level of FAM46C was correlated with the prognosis of most tumours, and low expression levels often suggested a poor prognosis. FAM46C was positively correlated with the abundance of CD4+ T cells, CD8+ T cells and plasma B lymphocytes in the tumour microenvironment. FAM46C exhibited a strong correlation with immunomodulatory pathways, immunomodulatory factors and immune markers. In addition, high FAM46C expression correlated with tumour mutational burden in acute myeloid leukaemia and microsatellite instability in endometrial cancer.

Conclusion: Our study suggests that FAM46C can be a potential prognostic marker for pan-cancer, is closely associated with immune regulation and may be an immune checkpoint to guide future clinical immunotherapy.

α5-nAChR associated with Ly6E modulates cell migration via TGF-β1/Smad signaling in non-small cell lung cancer

The α5-nicotinic acetylcholine receptor (α5-nAChR) is closely associated with nicotine-related lung cancer, offering a novel perspective for investigating the molecular pathogenesis of this disease. However, the mechanism by which α5-nAChR functions in lung carcinogenesis remains to be elucidated. Lymphocyte antigen 6 (Ly6) proteins, like snake three-finger alpha toxins such as α-bungarotoxin, can modulate nAChR signaling. Ly6E, a member of the Ly6 family, is a biomarker of poor prognosis in smoking-induced lung carcinogenesis and is involved in the regulation of TGF-β1/Smad signaling. Here, we explored the underlying mechanisms linking α5-nAChR and Ly6E in non-small cell lung cancer (NSCLC). The expression of α5-nAChR was correlated with Ly6 expression, smoking status and lower survival in NSCLC tissues. In vitro, α5-nAChR mediated Ly6E, the phosphorylation of the TGF-β1 downstream molecule Smad3 (pSmad3, a key mediator of TGF-β1 signaling), the epithelial-mesenchymal transition (EMT) markers Zeb1, N-cadherin and vimentin expression in NSCLC cells. The downregulation of Ly6E reduced α5-nAChR, pSmad3, Zeb1, N-cadherin and vimentin expression. Functionally, silencing both α5-nAChR and Ly6E significantly inhibited cell migration compared to silencing α5-nAChR or Ly6E alone. Furthermore, the functional effects of α5-nAchR and Ly6E were confirmed in chicken embryo chorioallantoic membrane (CAM) and mouse xenograft models. Therefore, our findings uncover a new interaction between α5-nAChR and Ly6E that inhibits cancer cell migration by modulating the TGF-β1/Smad signaling pathway in NSCLC, which may serve as a novel target for therapeutic intervention.

An Overview of the Recent Development of Anticancer Agents Targeting the HIF-1 Transcription Factor

Hypoxia, a characteristic feature of solid tumors, is associated with the malignant phenotype and therapy resistance of cancers. Hypoxia-inducible factor 1 (HIF-1), which is responsible for the metazoan adaptive response to hypoxia, has been recognized as a rational target for cancer therapy due to its critical functions in hypoxic regions. In order to efficiently inhibit its activity, extensive efforts have been made to elucidate the molecular mechanism underlying the activation of HIF-1. Here, we provide an overview of relevant research, particularly on a series of HIF-1 activators identified so far and the development of anticancer drugs targeting them.

High mRNA expression of LY6 gene family is associated with overall survival outcome in pancreatic ductal adenocarcinoma

Pancreatic cancer ranks one of the worst in overall survival outcome with a 5 year survival rate being less than 10%. Pancreatic cancer faces unique challenges in its diagnosis and treatment, such as the lack of clinically validated biomarkers and the immensely immunosuppressive tumor microenvironment. Recently, the LY6 gene family has received increasing attention for its multi-faceted roles in cancer development, stem cell maintenance, immunomodulation, and association with more aggressive and hard-to-treat cancers. A detailed study of mRNA expression of LY6 gene family and its association with overall survival (OS) outcome in pancreatic cancers is lacking. We used publicly available clinical datasets to analyze the mRNA expression of a set of LY6 genes and its effect on OS outcome in the context of the tumor microenvironment and immunomodulation. We used web-based tools Kaplan-Meier Plotter, cBioPortal, Oncomine and R-programming to analyze copy number alterations, mRNA expression and its association with OS outcome in pancreatic cancer. These analyses demonstrated that high expression of LY6 genes is associated with OS and disease free survival (DFS) outcome. High expression of LY6 genes and their association with OS outcome is dependent on the composition of tumor microenvironment. Considering that LY6 proteins are anchored to the outer cell membrane or secreted, making them readily accessible, these findings highlight the potential of LY6 family members in the future of pancreatic cancer diagnosis and treatment.

IFI27 may predict and evaluate the severity of respiratory syncytial virus infection in preterm infants

Background

Preterm infants are a special population that vulnerable to respiratory syncytial virus (RSV) infection and the lower respiratory tract infections (LRTIs) caused by RSV could be severe and even life-threating. The purpose of the present study was to identify candidate genes of preterm infants who are susceptible to RSV infection and provide a new insight into the pathogenesis of RSV infection.

Methods

Three datasets (GSE77087, GSE69606 and GSE41374) containing 183 blood samples of RSV infected patients and 33 blood samples of healthy controls from Gene Expression Omnibus (GEO) database were downloaded and the differentially expressed genes (DEGs) were screened out. The function and pathway enrichments were analyzed through Database for Annotation, Visualization and Integrated Discovery (DAVID) website. The protein-protein interaction (PPI) network for DEGs was constructed through Search Tool for the Retrieval of Interacting Genes (STRING). The module analysis was performed by Cytoscape software and hub genes were identified. Clinical verification was employed to verify the expression level of top five hub genes among 72 infants including 50 RSV infected patients and 22 non-RSV-infected patients hospitalized in our center. Further, the RSV infected infants with high-expression IFI27 and those with low-expression IFI27 were compared (defined as higher or lower than the median mRNA level). Finally, the gene set enrichment analysis (GSEA) focusing on IFI27 was carried out.

Results

Totally, 4028 DEGs were screened out and among which, 131 most significant DEGs were selected. Subsequently, 13 hub genes were identified, and function and pathway enrichments of hub genes mainly were: response to virus, defense response to virus, regulation of viral genome replication and regulation of viral life cycle. Furthermore, IFI27 was confirmed to be the most significantly expressed in clinical verification. Gene sets associated with calcium signaling pathway, arachidonic acid metabolism, extracellular matrix receptor interaction and so on were significantly enriched when IFI27 was highly expressed. Moreover, high-expression IFI27 was associated with more severe cases (p = 0.041), more requirements of mechanical ventilation (p = 0.034), more frequent hospitalization (p < 0.001) and longer cumulative hospital stay (p = 0.012).

Conclusion

IFI27 might serve to predict RSV infection and evaluate the severity of RSV infection in preterm infants.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41065-020-00167-5.

Preclinical optimization of Ly6E-targeted ADCs for increased durability and efficacy of anti-tumor response

Early success with brentuximab vedotin in treating classical Hodgkin lymphoma spurred an influx of at least 20 monomethyl auristatin E (MMAE) antibody-drug conjugates (ADCs) into clinical trials. While three MMAE-ADCs have been approved, most of these conjugates are no longer being investigated in clinical trials. Some auristatin conjugates show limited or no efficacy at tolerated doses, but even for drugs driving initial remissions, tumor regrowth and metastasis often rapidly occur. Here we describe the development of second-generation therapeutic ADCs targeting Lymphocyte antigen 6E (Ly6E) where the tubulin polymerization inhibitor MMAE (Compound 1) is replaced with DNA-damaging agents intended to drive increased durability of response. Comparison of a seco-cyclopropyl benzoindol-4-one (CBI)-dimer (compound 2) to MMAE showed increased potency, activity across more cell lines, and resistance to efflux by P-glycoprotein, a drug transporter commonly upregulated in tumors. Both anti-Ly6E-CBI and -MMAE conjugates drove single-dose efficacy in xenograft and patient-derived xenograft models, but seco-CBI-dimer conjugates showed reduced tumor outgrowth following multiple weeks of treatment, suggesting that they are less susceptible to developing resistance. In parallel, we explored approaches to optimize the targeting antibody. In contrast to immunization with recombinant Ly6E or Ly6E DNA, immunization with virus-like particles generated a high-affinity anti-Ly6E antibody. Conjugates to this antibody improve efficacy versus a previous clinical candidate both in vitro and in vivo with multiple cytotoxics. Conjugation of compound 2 to the second-generation antibody results in a substantially improved ADC with promising preclinical efficacy.

Hypercapnia and Hypoxia Stimulate Proliferation of Astrocytes and Neurons In Vitro

We compared proliferative activity and hypoxic tolerance in a co-culture of neurons and astrocytes in vitro after preliminary exposure to normobaric hypoxia and/or permissive hypercapnia in vivo. Preliminary hypoxic exposure increased the cell index throughout the 72-h period of observation, the effect of hypercapnia was observed on days 1 and 3 of the experiment, and the effect of hypercapnic hypoxia was noted only on day 1. Preliminary hypoxic exposure has a protective effect on nerve cells under conditions of chemical hypoxia. This suggests that hypercapnia and hypoxia activate proliferative activity of nerve cells, which can be viewed as a mechanism of their neuroprotective effectiveness.

Effects of Two Kinds of Iron Nanoparticles as Reactive Oxygen Species Inducer and Scavenger on the Transcriptomic Profiles of Two Human Leukemia Cells with Different Stemness

Leukemia is a common and lethal disease. In recent years, iron-based nanomedicines have been developed as a new ferroptosis inducer to leukemia. However, the cytotoxicity of iron nanoparticles to leukemia cells at the transcriptomic level remains unclear. This study investigated the effects of two kinds of iron nanoparticles, 2,3-Dimercaptosuccinic acid (DMSA)-coated Fe3O4 nanoparticles (FeNPs) as a reactive oxygen species (ROS) inducer and Prussian blue nanoparticles (PBNPs) as an ROS scavenger, on the transcriptomic profiles of two leukemia cells (KG1a and HL60) by RNA-Seq. As a result, 470 and 1690 differentially expressed genes (DEGs) were identified in the FeNP-treated HL60 and KG1a cells, respectively, and 2008 and 2504 DEGs were found in the PBNP-treated HL60 and KG1a cells, respectively. Among them, 14 common upregulated and 4 common downregulated DEGs were found, these genes were representative genes that play key roles in lipid metabolism (GBA and ABCA1), iron metabolism (FTL, DNM1, and TRFC), antioxidation (NQO1, GCLM, and SLC7A11), vesicle traffic (MCTP2, DNM1, STX3, and BIN2), and innate immune response (TLR6, ADGRG3, and DDX24). The gene ontology revealed that the mineral absorption pathway was significantly regulated by PBNPs in two cells, whereas the lipid metabolism and HIF-1 signaling pathways were significantly regulated by FeNPs in two cells. This study established the gene signatures of two kinds of nanoparticles in two leukemia cells, which revealed the main biological processes regulated by the two kinds of iron nanoparticles. These data shed new insights into the cytotoxicity of iron nanoparticles that differently regulate ROS in leukemia cells with variant stemness.

Dendritic Cell-Based Therapy Using LY6E Peptide with a Putative Role Against Colorectal Cancer

INTRODUCTION

Albeit early stage gastrointestinal (GI) carcinomas have a good prognosis if treated with surgery, diagnosis is often confirmed at a late stage and efficacious drugs are lacking. Recent progress in immune-based therapies has focused on dendritic cells (DCs), aiming to elicit tumor-specific responses by inducing immunological memory. Our previous microarray study indicated that a biomarker, termed lymphocyte antigen-6E (LY6E), is commonly overexpressed in two potentially lethal GI cancers: those of colon and stomach. In this study, we examined the antigenic potency of LY6E in stimulating DCs.

METHODS

Following isolation, differentiation, and maturation of mononuclear cells, DCs were pulsed with LY6E peptide, a protein related to major histocompatibility complex (MHC) class I/II. Subsequently, DCs were co-cultured with mouse splenocytes to assess antigen-specific T-cell proliferation. Elucidated cytotoxic T-lymphocyte responses were assessed using subcutaneous colorectal murine tumor models.

RESULTS

Our in vitro results suggest that DCs loaded with LY6E peptide antigen are capable of stimulating and inducing proliferation of murine T-cells. Furthermore, our in vivo results demonstrate that LY6E peptide has a substantial impact on provoking immune responses against induced colon cancer in mice.

DISCUSSION

In conclusion, based on the overexpression of LY6E in colorectal, gastric, and pancreatic cancers, the role of this peptide should be further investigated with a goal of developing new therapies for these challenging diseases.

Relating GPI-Anchored Ly6 Proteins uPAR and CD59 to Viral Infection

The Ly6 (lymphocyte antigen-6)/uPAR (urokinase-type plasminogen activator receptor) superfamily protein is a group of molecules that share limited sequence homology but conserved three-fingered structures. Despite diverse cellular functions, such as in regulating host immunity, cell adhesion, and migration, the physiological roles of these factors in vivo remain poorly characterized. Notably, increasing research has focused on the interplays between Ly6/uPAR proteins and viral pathogens, the results of which have provided new insight into viral entry and virus-host interactions. While LY6E (lymphocyte antigen 6 family member E), one key member of the Ly6E/uPAR-family proteins, has been extensively studied, other members have not been well characterized. Here, we summarize current knowledge of Ly6/uPAR proteins related to viral infection, with a focus on uPAR and CD59. Our goal is to provide an up-to-date view of the Ly6/uPAR-family proteins and associated virus-host interaction and viral pathogenesis.

Emerging Role of LY6E in Virus-Host Interactions

As a canonical lymphocyte antigen-6/urokinase-type plasminogen activator receptor Ly6/uPAR family protein, lymphocyte antigen 6 complex, locus E (LY6E), plays important roles in immunological regulation, T cell physiology, and oncogenesis. Emerging evidence indicates that LY6E is also involved in the modulation of viral infection. Consequently, viral infection and associated pathogenesis have been associated with altered LY6E gene expression. The interaction between viruses and the host immune system has offered insights into the biology of LY6E. In this review, we summarize the current knowledge of LY6E in the context of viral infection, particularly viral entry.

Molecular prognosticators in clinically and pathologically distinct cohorts of head and neck squamous cell carcinoma-A meta-analysis approach

Head and neck squamous cell carcinomas (HNSCC) includes multiple subsites that exhibit differential treatment outcome, which is in turn reflective of tumor stage/histopathology and molecular profile. This study hypothesized that the molecular profile is an accurate prognostic adjunct in patients triaged based on clinico-pathological characteristics. Towards this effect, publically available micro-array datasets (n = 8), were downloaded, classified based on HPV association (n = 83) and site (tongue n = 88; laryngopharynx n = 53; oropharynx n = 51) and re-analyzed (Genespring; v13.1). The significant genes were validated in respective cohorts in The Cancer Genome Atlas (TCGA) for correlation with clinico-pathological parameters/survival. The gene entities (n = 3258) identified from HPV based analysis, when validated in TCGA identified the subset specifically altered in HPV+ HNSCC (n = 63), with three genes showing survival impact (RPP25, NUDCD2, NOVA1). Site-specific meta-analysis identified respective differentials (tongue: 3508, laryngopharynx: 4893, oropharynx: 2386); validation in TCGA revealed markers with high incidence (altered in >10% of patients) in tongue (n = 331), laryngopharynx (n = 701) and oropharynx (n = 404). Assessment of these genes in clinical sub-cohorts of TCGA indicated that early stage tongue (MTFR1, C8ORF33, OTUD6B) and laryngeal cancers (TWISTNB, KLHL13 and UBE2Q1) were defined by distinct prognosticators. Similarly, correlation with perineural/angiolymophatic invasion, identified discrete marker panels with survival impact (tongue: NUDCD1, PRKC1; laryngopharynx: SLC4A1AP, PIK3CA, AP2M1). Alterations in ANO1, NUDCD1, PIK3CA defined survival in tongue cancer patients with nodal metastasis (node+ECS-), while EPS8 is a significant differential in node+ECS- laryngopharyngeal cancers. In oropharynx, wherein HPV is a major etiological factor, distinct prognosticators were identified in HPV+ (ECHDC2, HERC5, GGT6) and HPV- (GRB10, EMILIN1, FNDC1). Meta-analysis in combination with TCGA validation carried out in this study emphasized on the molecular heterogeneity inherent within HNSCC; the feasibility of leveraging this information for improving prognostic efficacy is also established. Subject to large scale clinical validation, the marker panel identified in this study can prove to be valuable prognostic adjuncts.

Emerging Role of Lymphocyte Antigen-6 Family of Genes in Cancer and Immune Cells

Stem Cell Antigen-1 (Sca-1/Ly6A) was the first identified member of the Lymphocyte antigen-6 (Ly6) gene family. Sca-1 serves as a marker of cancer stem cells and tissue resident stem cells in mice. The Sca-1 gene is located on mouse chromosome 15. While a direct homolog of Sca-1 in humans is missing, human chromosome 8—the syntenic region to mouse chromosome 15—harbors several genes containing the characteristic domain known as LU domain. The function of the LU domain in human LY6 gene family is not yet defined. The LY6 gene family proteins are present on human chromosome 6, 8, 11, and 19. The most interesting of these genes are located on chromosome 8q24.3, a frequently amplified locus in human cancer. Human LY6 genes represent novel biomarkers for poor cancer prognosis and are required for cancer progression in addition to playing an important role in immune escape. Although the mechanism associated with these phenotype is not yet clear, it is timely to review the current literature in order to address the critical need for future advancements in this field. This review will summarize recent findings which describe the role of human LY6 genes—LY6D, LY6E, LY6H, LY6K, PSCA, LYPD2, SLURP1, GML, GPIHBP1, and LYNX1; and their orthologs in mice at chromosome 15.

CD4-Dependent Modulation of HIV-1 Entry by LY6E

Lymphocyte antigen 6E (LY6E) is a GPI-anchored, interferon-inducible protein that has been shown to modulate viral infection in a cell type-dependent manner. Our recent work showed that LY6E promotes HIV-1 infection in some high-CD4-expressing cells, including human peripheral blood mononuclear cells (PBMCs) and the SupT1 cell line. In this work, we provide evidence that LY6E inhibits HIV-1 entry and spread in low-CD4-expressing Jurkat cells and human monocyte-derived macrophages (MDMs) through downregulation of the viral receptor CD4. We found that knockdown of LY6E in Jurkat cells and MDMs increases HIV-1 infection, yet overexpression of LY6E in Jurkat cells inhibits HIV-1 entry and replication. LY6E was found to be colocalized with CD4 on the plasma membrane of Jurkat cells and MDMs and enhances CD4 internalization. We artificially manipulated the CD4 level in Jurkat and SupT1 cells and found that overexpression of CD4 in Jurkat cells overcomes the inhibitory effect of LY6E; conversely, blocking the function of CD4 in SupT1 with a neutralizing antibody eliminates the enhancement of LY6E on HIV-1 entry. The CD4-dependent inhibitory phenotype of LY6E in low-CD4-expressing human MDMs can be recapitulated for a panel of transmitted founder viruses and laboratory-adapted HIV-1 strains. Given that HIV-1 can target low-CD4-expressing cells during acute infection yet replicates efficiently in high-CD4-expressing T cells at the late stage of disease, our observation that LY6E differentially modulates HIV-1 replication in a CD4-dependent manner has implications for understanding the complex roles of interferon (IFN)-induced proteins in AIDS pathogenesis.IMPORTANCE The role of IFN-induced genes (ISGs) in viral infection remains incompletely understood. While most ISGs are antiviral, some ISGs have been shown to promote viral infection, including HIV-1 infection. We previously showed that IFN-inducible LY6E protein promotes HIV-1 infection in human PMBCs and high-CD4-expressing SupT1 cells. Here we found that LY6E inhibits HIV-1 entry and replication in low-CD4-expressing MDMs and Jurkat cells. Mechanistically, we demonstrated that LY6E downregulates the cell surface receptor CD4, thus impairing the virus binding to target cells. This is in contrast to the situation of high-CD4-expressing cells, where LY6E predominantly promotes viral membrane fusion. The opposing role of IFN-inducible LY6E in modulating HIV-1 infection highlights the complex roles of ISGs in viral infection and viral pathogenesis.

HIF-1-Dependent Reprogramming of Glucose Metabolic Pathway of Cancer Cells and Its Therapeutic Significance

Normal cells produce adenosine 5'-triphosphate (ATP) mainly through mitochondrial oxidative phosphorylation (OXPHOS) when oxygen is available. Most cancer cells, on the other hand, are known to produce energy predominantly through accelerated glycolysis, followed by lactic acid fermentation even under normoxic conditions. This metabolic phenomenon, known as aerobic glycolysis or the Warburg effect, is less efficient compared with OXPHOS, from the viewpoint of the amount of ATP produced from one molecule of glucose. However, it and its accompanying pathway, the pentose phosphate pathway (PPP), have been reported to provide advantages for cancer cells by producing various metabolites essential for proliferation, malignant progression, and chemo/radioresistance. Here, focusing on a master transcriptional regulator of adaptive responses to hypoxia, the hypoxia-inducible factor 1 (HIF-1), we review the accumulated knowledge on the molecular basis and functions of the Warburg effect and its accompanying pathways. In addition, we summarize our own findings revealing that a novel HIF-1-activating factor enhances the antioxidant capacity and resultant radioresistance of cancer cells though reprogramming of the glucose metabolic pathway.

Emerging Role of Novel Biomarkers of Ly6 Gene Family in Pan Cancer

Stem cell antigen-1 (Sca-1) is the first identified member of mouse Ly6 gene family. We discovered that Sca-1 disrupts TGFβ signaling and enhances mammary tumorigenesis in a DMBA-induced mammary tumor model. Sca-1 gene is lost during evolution in humans. Human Ly6 genes Ly6D, LyE, LyH, and LyK on human chromosome 8q24.3 genes are syntenic to the mouse chromosome 15 where Sca-1 is located. We found that Ly6D, E, H, and K are upregulated in human cancer compared to normal tissue and that the increased expression of these genes are associated with poor prognosis of multiple types of human cancer. Several other groups have indicated increased expression of Ly6 genes in human cancer. Here we described the relevance of expression of human Ly6D, LyE, LyH, and LyK in functioning of normal tissues and tumor progression.

Current insights and future perspectives of hypoxia-inducible factor-targeted therapy in cancer

Hypoxia-inducible factors (HIFs) are transcription factors that are expressed in the hypoxic tumor microenvironment. They are involved in the cellular adaptations by improving the metabolism of glucose and enhance the expression of vascular endothelial growth factor, platelet-derived growth factor and angiopoietin, thereby they play a pivotal role in the angiogenesis. Hypoxia can increase the expression of nuclear factor-kappa B which promotes the pro-inflammatory status. Abnormally high angiogenesis, inflammation, antiapoptosis and anaerobic glycolysis can augment the progression and metastasis of tumor. Hence, HIFs remain one of the promising antiangiogenic agents as well as a direct target for interfering with the energetic of cancer cells in order to regulate the tumor growth. Previous studies found agents like topotecan, acriflavine and benzophenone-1B etc. to block the HIF-α mediated angiogenesis. The effect is mediated through interfering any one of the processes in the activation of HIF such as nuclear translocation of HIF-1α; dimerization of HIF-1α with β in the nucleus; HIF-1α/HIF-2α mediated induction of VEGF or translation of HIF-1α mRNA. Despite the experimental studies on the inhibitory molecules of HIFs, none of them are available for the clinical use. This review article discusses the recent update on the HIF-targeted therapy in cancer.

Hypoxia-inducible factor-1 promotes cancer progression through activating AKT/Cyclin D1 signaling pathway in osteosarcoma

OBJECTIVE

Osteosarcoma is an aggressive malignant neoplasm, which commonly afflicts patients of 20-30 years of age, and its morbidity has increased markedly in recent years. Certain genes and signal pathways have been identified to exert key roles in osteosarcoma progression. Here, we set out to characterize in more detail of the role of HIF-1/AKT/Cyclin D1 pathway in the progression of osteosarcoma.

METHODS

Immunohistochemistry, western blot and qPCR were used to test the protein or mRNA levels of HIF-1 in osteosarcoma tissues or adjacent nontumor tissues. MTT, clone formation, wound healing, Transwell, in vivo tumorigenesis, flow cytometry and western blot analysis were used to determine cell proliferation, clone formation ability, migration, invasion, tumorigenesis, and cell apoptosis in MG63 and U2OS cells, respectively. Immunoprecipitation and immunofluorescence assays were performed to investigate the protein-protein interaction between HIF-1α and proteins related to signal pathways.

RESULTS

HIF-1 was overexpressed in osteosarcoma tissues and cell lines, which promoted cell proliferation, clone formation, migration, invasion and inhibited cell apoptosis. Results also demonstrated that HIF-1 combined with AKT, and there might be a positive loop between the two proteins of HIF-1 and AKT, then the protein-protein interaction up-regulated the expression of Cyclin D1 in protein level, but not mRNA level, made Cyclin D1 protein more stable, triggered cell proliferation, clone formation, tumorigenesis, but inhibited cell apoptosis.

CONCLUSIONS

The present study showed that HIF-1 modulated Cyclin D1 expression might through shaping a positive loop with AKT proteins. Additionally, HIF-1α promoted the tumor cells growth, migration and invasion in osteosarcoma through the activation of the AKT/Cyclin D1 signal cascade. We proposed that HIF-1 could be served as a marker for distinguishing osteosarcoma and an effective therapeutic target for osteosarcoma.

Regulatory mechanisms of hypoxia-inducible factor 1 activity: Two decades of knowledge

Hypoxia‐inducible factor 1 (HIF‐1) is a transcriptional activator of various genes related to cellular adaptive responses to hypoxia. Dysfunctions in the regulatory systems of HIF‐1 activity have been implicated in the pathogenesis of various diseases including malignant tumors and, thus, elucidating the molecular mechanisms underlying the activation of HIF‐1 is eagerly desired for the development of novel anti‐cancer strategies. The importance of oxygen‐dependent and ubiquitin‐mediated proteolysis of the regulatory subunit of HIF‐1 (HIF‐1α) was first reported in 1997. Since then, accumulating evidence has shown that HIF‐1α may become stable and active even under normoxic conditions; for example, when disease‐associated genetic and functional alterations in some genes trigger the aberrant activation of HIF‐1 regardless of oxygen conditions. We herein review the last two decades of knowledge, since 1997, on the regulatory mechanisms of HIF‐1 activity from conventional oxygen‐ and proteolysis‐dependent mechanisms to up‐to‐the‐minute information on cancer‐associated genetic and functional alteration‐mediated mechanisms.

A circadian clock gene, PER2, activates HIF-1 as an effector molecule for recruitment of HIF-1α to promoter regions of its downstream genes

Hypoxia-inducible factor 1 (HIF-1) is a transcription factor functioning in cellular adaptive responses to hypoxia. Recent studies have suggested that HIF-1 activity is upregulated by one of the important circadian clock genes, period circadian clock 2 (PER2); however, its underlying mechanism remains unclear. Here, we show that PER2 functions as an effector protein for the recruitment of HIF-1α to its cognate enhancer sequence, the hypoxia-response element (HRE). We found that the forced expression of PER2 enhanced HIF-1 activity without influencing expression levels of the regulatory subunit of HIF-1, HIF-1α, at either mRNA or protein levels. A series of coimmunoprecipitation-based experiments revealed that PER2 interacted with HIF-1α and facilitated the recruitment of HIF-1α to HRE derived from vascular endothelial growth factor (VEGF) promoter. The PER2-mediated activation of HIF-1 was observed only when the asparagine residue at position 803 of HIF-1α (HIF-1α N803) was kept unhydroxylated by hypoxic stimulation, by introducing an N803A point mutation, or by an inhibitor of N803-dioxygenase, deferoxamine. However, the extent of PER-2-HIF-1α interaction was equivalent regardless of the N803 hydroxylation status. Taken together, these results suggest that, with the help of an unknown sensor molecule for the N803 hydroxylation status, PER2 functions as an effector molecule for the recruitment of HIF-1 to promoter regions of its downstream genes. Our findings reveal a novel regulatory step in the activation of HIF-1, which can be targeted to develop therapeutic strategies against HIF-1-related diseases, such as cancers.

Emodin and rhein decrease levels of hypoxia-inducible factor-1α in human pancreatic cancer cells and attenuate cancer cachexia in athymic mice carrying these cells

The transcription factor hypoxia-inducible factor-1 (HIF-1) consists of oxygen-sensitive HIF-1α and constitutive HIF-1β. HIF-1α is undetectable in normal cells, but cancer cells frequently express HIF-1α to support their growth, angiogenesis, and high glycolysis (also known as the Warburg effect). The Warburg effect in cancer cells increases energy expenditure and thus participates in cancer-induced metabolic disorder, cancer cachexia. In the present study, we investigated whether two components of Rheum palmatum, emodin and rhein, inhibited HIF-1α expression in human pancreatic cancer cells and whether the inhibiting effect, if any, attenuated cancer cachexia. Using Western blotting, we demonstrated that emodin and rhein decreased HIF-1α expression in MiaPaCa2 and four other human pancreatic cancer cell lines. We also examined HIF-1α expression when MiaPaCa2 cells were exposed to PX-478, noscapine, and phenethyl isothiocyanate, as these compounds were known to inhibit HIF-1α expression in different cancer cells. PX-478 and noscapine inhibited HIF-1α expression to a less extent than emodin and rhein, and phenethyl isothiocyanate did not inhibit HIF-1α expression in tested concentrations. We obtained evidence that emodin and rhein decreased HIF-1α by decreasing its biosynthesis but not gene transcription or protein stability. When MiaPaCa2 cells were implanted in athymic mice, emodin and rhein inhibited cancer-cell growth and HIF-1α expression. In these athymic mice, emodin and rhein also attenuated two pathological constituents of cancer cachexia, namely high hepatic gluconeogenesis and skeletal-muscle proteolysis. In conclusion, emodin and rhein decrease pancreatic cancer cell's growth and HIF-1α expression and attenuate cancer cachexia in the athymic mice carrying the cancer cells.

UCHL1-HIF-1 axis-mediated antioxidant property of cancer cells as a therapeutic target for radiosensitization

Hypoxia-inducible factor 1 (HIF-1) has been recognized as an important mediator of the reprogramming of carbohydrate metabolic pathways from oxidative phosphorylation to accelerated glycolysis. Although this reprogramming has been associated with the antioxidant and radioresistant properties of cancer cells, gene networks triggering the HIF-1-mediated reprogramming and molecular mechanisms linking the reprogramming with radioresistance remain to be determined. Here, we show that Ubiquitin C-terminal hydrolase-L1 (UCHL1), which we previously identified as a novel HIF-1 activator, increased the radioresistance of cancer cells by producing an antioxidant, reduced glutathione (GSH), through HIF-1-mediated metabolic reprogramming. A luciferase assay to monitor HIF-1 activity demonstrated that the overexpression of UCHL1, but not its deubiquitination activity-deficient mutant (UCHL1 C90S), upregulated HIF-1 activity by stabilizing the regulatory subunit of HIF-1 (HIF-1α) in a murine breast cancer cell line, EMT6. UCHL1 overexpression induced the reprogramming of carbohydrate metabolism and increased NADPH levels in a pentose phosphate pathway (PPP)-dependent manner. The UCHL1-mediated reprogramming elevated intracellular GSH levels, and consequently induced a radioresistant phenotype in a HIF-1-dependent manner. The pharmacological inhibition of PPP canceled the UCHL1-mediated radioresistance. These results collectively suggest that cancer cells acquire antioxidant and radioresistant phenotypes through UCHL1-HIF-1-mediated metabolic reprogramming including the activation of PPP and provide a rational basis for targeting this gene network for radiosensitization.