Down-regulation of LHPP in cervical cancer influences cell proliferation, metastasis and apoptosis by modulating AKT

Nphos: Database and Predictor of Protein N-phosphorylation

Protein N-phosphorylation is widely present in nature and participates in various biological processes. However, current knowledge on N-phosphorylation is extremely limited compared to that on O-phosphorylation. In this study, we collected 11,710 experimentally verified N-phosphosites of 7344 proteins from 39 species and subsequently constructed the database Nphos to share up-to-date information on protein N-phosphorylation. Upon these substantial data, we characterized the sequential and structural features of protein N-phosphorylation. Moreover, after comparing hundreds of learning models, we chose and optimized gradient boosting decision tree (GBDT) models to predict three types of human N-phosphorylation, achieving mean area under the receiver operating characteristic curve (AUC) values of 90.56%, 91.24%, and 92.01% for pHis, pLys, and pArg, respectively. Meanwhile, we discovered 488,825 distinct N-phosphosites in the human proteome. The models were also deployed in Nphos for interactive N-phosphosite prediction. In summary, this work provides new insights and points for both flexible and focused investigations of N-phosphorylation. It will also facilitate a deeper and more systematic understanding of protein N-phosphorylation modification by providing a data and technical foundation. Nphos is freely available at http://www.bio-add.org/Nphos/ and http://ppodd.org.cn/Nphos/.

Histidine Phosphorylation: Protein Kinases and Phosphatases

Phosphohistidine (pHis) is a reversible protein post-translational modification (PTM) that is currently poorly understood. The P-N bond in pHis is heat and acid-sensitive, making it more challenging to study than the canonical phosphoamino acids pSer, pThr, and pTyr. As advancements in the development of tools to study pHis have been made, the roles of pHis in cells are slowly being revealed. To date, a handful of enzymes responsible for controlling this modification have been identified, including the histidine kinases NME1 and NME2, as well as the phosphohistidine phosphatases PHPT1, LHPP, and PGAM5. These tools have also identified the substrates of these enzymes, granting new insights into previously unknown regulatory mechanisms. Here, we discuss the cellular function of pHis and how it is regulated on known pHis-containing proteins, as well as cellular mechanisms that regulate the activity of the pHis kinases and phosphatases themselves. We further discuss the role of the pHis kinases and phosphatases as potential tumor promoters or suppressors. Finally, we give an overview of various tools and methods currently used to study pHis biology. Given their breadth of functions, unraveling the role of pHis in mammalian systems promises radical new insights into existing and unexplored areas of cell biology.

The effect of overexpression of CyPA on gene expression in human umbilical vein endothelial cells

The aim of this study is to screen the differentially expressed genes and genes with alternative splicing in PPIA overexpressing cells by transcriptome sequencing. Transcriptome sequencing was performed to identify differentially expressed genes and genes with altered alternative splicing in PPIA overexpressing cells and results were validated by real-time quantitative polymerase chain reaction. The biological function and pathways of those genes were further explored through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes analyses. A total of 157 significantly upregulated genes and 171 significantly downregulated genes were identified in PPIA overexpressing cells, and the splicing pattern of LHPP, APH1A, BRD1, and ORAI3 was found to be altered. GO analyses showed that the most enriched GO terms of the 157 upregulated genes included extracellular region, protein binding, and metal ion, and the most enriched GO terms of the 171 downregulated genes included binding neuron projection, protein binding, and endoplasmic reticulum unfolded protein response. Kyoto Encyclopedia of Genes and Genomes analyses showed that the 157 upregulated genes were mainly enriched in gastric acid secretion, Mitogen-activated protein kinase signaling pathway, etc, and the 171 downregulated genes were mainly enriched in transcriptional misregulation in cancer, Tumor necrosis factor signaling pathway, etc. The overexpression of PPIA in human umbilical vein endothelial cells causes changes in the expression of downstream genes and induces alternative splicing in multiple genes. PPIA alters the expression or the alternative splicing pattern of downstream genes, leading to pathogenesis of vascular endothelial injury by high glucose mediated through CyPA.

Oncolytic adenovirus encoding LHPP exerts potent antitumor effect in lung cancer

LHPP has been shown to be a new tumor suppressor, and has a tendency to be under-expressed in a variety of cancers. Oncolytic virotheray is a promising therapeutics for lung cancer in recent decade years. Here we successfully constructed a new recombinant oncolytic adenovirus GD55-LHPP and investigated the effect of GD55-LHPP on the growth of lung cancer cells in vitro and in vivo. The results showed that LHPP had lower expression in either lung cancer cells or clinical lung cancer tissues compared with normal cells or tissues, and GD55-LHPP effectively mediated LHPP expression in lung cancer cells. GD55-LHPP could effectively inhibit the proliferation of lung cancer cell lines and rarely affected normal cell growth. Mechanically, the oncolytic adenovirus GD55-LHPP was able to induce stronger apoptosis of lung cancer cells compared with GD55 through the activation of caspase signal pathway. Notably, GD55-LHPP also activated autophagy-related signal pathway. Further, GD55-LHPP efficiently inhibited tumor growth in lung cancer xenograft in mice and prolonged animal survival rate compared with the control GD55 or PBS. In conclusion, the novel construct GD55-LHPP provides a valuable strategy for lung cancer-targeted therapy and develop the role of tumor suppress gene LHPP in lung cancer gene therapy.

Activation of AMPK inhibits cervical cancer growth by hyperacetylation of H3K9 through PCAF

BACKGROUND

Dysregulation in histone acetylation, a significant epigenetic alteration closely associated with major pathologies including cancer, promotes tumorigenesis, inactivating tumor-suppressor genes and activating oncogenic pathways. AMP-activated protein kinase (AMPK) is a cellular energy sensor that regulates a multitude of biological processes. Although a number of studies have identified the mechanisms by which AMPK regulates cancer growth, the underlying epigenetic mechanisms remain unknown.

METHODS

The impact of metformin, an AMPK activator, on cervical cancer was evaluated through assessments of cell viability, tumor xenograft model, pan-acetylation analysis, and the role of the AMPK-PCAF-H3K9ac signaling pathway. Using label-free quantitative acetylproteomics and chromatin immunoprecipitation-sequencing (ChIP) technology, the activation of AMPK-induced H3K9 acetylation was further investigated.

RESULTS

In this study, we found that metformin, acting as an AMPK agonist, activates AMPK, thereby inhibiting the proliferation of cervical cancer both in vitro and in vivo. Mechanistically, AMPK activation induces H3K9 acetylation at epigenetic level, leading to chromatin remodeling in cervical cancer. This also enhances the binding of H3K9ac to the promoter regions of multiple tumor suppressor genes, thereby promoting their transcriptional activation. Furthermore, the absence of PCAF renders AMPK activation incapable of inducing H3K9 acetylation.

CONCLUSIONS

In conclusion, our findings demonstrate that AMPK mediates the inhibition of cervical cancer growth through PCAF-dependent H3K9 acetylation. This discovery not only facilitates the clinical application of metformin but also underscores the essential role of PCAF in AMPK activation-induced H3K9 hyperacetylation.

Upregulation of LHPP by saRNA inhibited hepatocellular cancer cell proliferation and xenograft tumor growth

Hepatocellular carcinoma (HCC) is the most common primary liver cancer worldwide and no pharmacological treatment is available that can achieve complete remission of HCC. Phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) is a recently identified HCC tumor suppressor gene which plays an important role in the development of HCC and its inactivation and reactivation has been shown to result in respectively HCC tumorigenesis and suppression. Small activating RNAs (saRNAs) have been used to achieve targeted activation of therapeutic genes for the restoration of their encoded protein through the RNAa mechanism. Here we designed and validated saRNAs that could activate LHPP expression at both the mRNA and protein levels in HCC cells. Activation of LHPP by its saRNAs led to the suppression of HCC proliferation, migration and the inhibition of Akt phosphorylation. When combined with targeted anticancer drugs (e.g., regorafenib), LHPP saRNA exhibited synergistic effect in inhibiting in vitro HCC proliferation and in vivo antitumor growth in a xenograft HCC model. Findings from this study provides further evidence for a tumor suppressor role of LHPP and potential therapeutic value of restoring the expression of LHPP by saRNA for the treatment of HCC.

LHPP expression in triple-negative breast cancer promotes tumor growth and metastasis by modulating the tumor microenvironment

Triple-negative breast cancer (TNBC) is a highly aggressive and metastatic form of breast cancer that lacks an effective targeted therapy. To identify new therapeutic targets, we investigated the phosphohistidine phosphatase, LHPP, which has been implicated in the development of several types of cancer. However, the full significance of LHPP in cancer progression remains unclear due to our limited understanding of its molecular mechanism. We found that levels of the LHPP phosphohistidine phosphatase were significantly increased in human breast cancer patients compared to normal adjacent tissues, with the highest levels in the TNBC subtype. When LHPP was knocked out in the MDA-MB-231 human TNBC cell line, cell proliferation, wound healing capacity, and invasion were significantly reduced. However, LHPP knockout in TNBC cells did not affect the phosphohistidine protein levels. Interestingly, LHPP knockout in MDA-MB-231 cells delayed tumor growth and reduced metastasis when orthotopically transplanted into mouse mammary glands. To investigate LHPP's role in breast cancer progression, we used next-generation sequencing and proximity-labeling proteomics, and found that LHPP regulates gene expression in chemokine-mediated signaling and actin cytoskeleton organization. Depletion of LHPP reduced the presence of tumor-infiltrating macrophages in mouse xenografts. Our results uncover a new tumor promoter role for LHPP phosphohistidine phosphatase in TNBC and suggest that targeting LHPP phosphatase could be a potential therapeutic strategy for TNBC.

Phospholysine phosphohistidine inorganic pyrophosphate phosphatase suppresses insulin-like growth factor 1 receptor expression to inhibit cell adhesion and proliferation in gastric cancer

Phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) has recently emerged as a novel tumor suppressor. Researchers have observed that LHPP plays a crucial role in inhibiting proliferation, growth, migration, invasion, and cell metabolism across various cancers. Nevertheless, the specific functions and underlying mechanisms of LHPP as a tumor suppressor in gastric cancer (GC) require further exploration. The expression of LHPP was assessed in human GC specimens and cell lines. Various assays were employed to evaluate the impact of LHPP on GC cells. RNA sequencing and Gene Set Enrichment Analysis were conducted to unravel the mechanism through which LHPP regulates GC cell behavior. Additionally, xenograft nude mouse models were utilized to investigate the in vivo effects of LHPP. The findings indicate that LHPP, functioning as a tumor suppressor, is downregulated in both GC tissues and cells. LHPP emerges as an independent risk factor for GC patients, and its expression level exhibits a positive correlation with patient prognosis. LHPP exerts inhibitory effects on the adhesion and proliferation of GC cells by suppressing the expression of insulin-like growth factor 1 receptor (IGF1R) and modulating downstream signaling pathways. Consequently, LHPP holds potential as a biomarker for targeted therapy involving IGF1R inhibition in GC patients.

The role of the methyltransferase METTL3 in prostate cancer: a potential therapeutic target

The incidence of prostate cancer (PCa), the most prevalent malignancy, is currently at the forefront. RNA modification is a subfield of the booming field of epigenetics. To date, more than 170 types of RNA modifications have been described, and N6-methyladenosine (m6A) is the most abundant and well-characterized internal modification of mRNAs involved in various aspects of cancer progression. METTL3, the first identified key methyltransferase, regulates human mRNA and non-coding RNA expression in an m6A-dependent manner. This review elucidates the biological function and role of METTL3 in PCa and discusses the implications of METTL3 as a potential therapeutic target for future research directions and clinical applications.

Single-cell analysis identifies phospholysine phosphohistidine inorganic pyrophosphate phosphatase as a target in ulcerative colitis

BACKGROUND

Ulcerative colitis (UC) is a chronic gastrointestinal disorder characterized by inflammation and ulceration, representing a significant predisposition to colorectal cancer. Recent advances in single-cell RNA sequencing (scRNA-seq) technology offer a promising avenue for dissecting the complex cellular inter-actions and molecular signatures driving UC pathology.

AIM

To utilize scRNA-seq technology to dissect the complex cellular interactions and molecular signatures that underlie UC pathology.

METHODS

In this research, we integrated and analyzed the scRNA-seq data from UC patients. Moreover, we conducted mRNA and protein level assays as well as pathology-related staining tests on clinical patient samples.

RESULTS

In this study, we identified the sustained upregulation of inflammatory response pathways during UC progression, characterized the features of damaged endo-thelial cells in colitis. Furthermore, we uncovered the downregulation of phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) has a negative correlation with signal transducer and activator of transcription 3. Significant downregulation of LHPP in UC patient tissues and plasma suggests that LHPP may serve as a potential therapeutic target for UC. This paper highlights the importance of LHPP as a potential key target in UC and unveils its potential role in inflammation regulation.

CONCLUSION

The findings suggest that LHPP may serve as a potential therapeutic target for UC, emphasizing its importance as a potential key target in UC and unveiling its role in inflammation regulation.

The role of RNA modification in urological cancers: mechanisms and clinical potential

RNA modification is a post-transcriptional level of regulation that is widely distributed in all types of RNAs, including mRNA, tRNA, rRNA, miRNA, and lncRNA, where N6-methyladenine (m6A) is the most abundant mRNA methylation modification. Significant evidence has depicted that m6A modifications are closely related to human diseases, especially cancer, and play pivotal roles in RNA transcription, splicing, stabilization, and translation processes. The most common urological cancers include prostate, bladder, kidney, and testicular cancers, accounting for a certain proportion of human cancers, with an ever-increasing incidence and mortality. The recurrence, systemic metastasis, poor prognosis, and drug resistance of urologic tumors have prompted the identification of new therapeutic targets and mechanisms. Research on m6A modifications may provide new solutions to the current puzzles. In this review, we provide a comprehensive overview of the key roles played by RNA modifications, especially m6A modifications, in urologic cancers, as well as recent research advances in diagnostics and molecularly targeted therapies.

The histidine phosphatase LHPP of Penaeus vannamei is involved in shrimp hemocytes apoptosis

LHPP (Phospholysine Phosphohistidine Inorganic Pyrophosphate Phosphatase) is a protein histidine phosphatase that modulates a hidden posttranslational modification called histidine phosphorylation. LHPP also acts as a tumor suppressor, which plays a pivotal role in various cellular processes. However, whether LHPP participates in the regulation of invertebrate's immunity is still unknown. Here we characterized a LHPP homolog in P. vannamei (designated PvLHPP), with a 807 bp length of open reading frame (ORF) encoding a putative protein of 268 amino acids. Sequence analysis revealed that PvLHPP contains a typical hydrolase 6 and hydrolase-like domain, which was conserved from invertebrate to vertebrate. PvLHPP was ubiquitously expressed in tissues and induced in hemocyte and hepatopancreas by Vibrio parahaemolyticus, Streptococcus iniae and white spot syndrome virus (WSSV) challenge, indicating that PvLHPP participated in the immune responses. Moreover, silencing of PvLHPP followed by V. parahaemolyticus inhibited hemocyte apoptosis. This study enriches our current insight on shrimp immunity, and provides novel perspective to understand immune-regulatory role of PvLHPP.

The functional roles of m6A modification in prostate cancer

Prostate cancer (PCa) is the most prevalent malignancy of the male genitourinary system, and its etiology suggests that genetics is an essential risk factor for its development and progression, while exogenous factors may have an significant impact on this risk. Initial diagnosis of advanced PCa is relatively frequent, and androgen deprivation therapy (ADT) is the predominant standard of care for PCa and the basis for various novel combination therapy regimens, and is often required throughout the patient's subsequent treatment. Although diagnostic modalities and treatment options are evolving, some patients suffer from complications, including biochemical relapse, metastasis and treatment resistance. Mechanisms of PCa pathogenesis and progression have been the focus of research. N6-methyladenosine (m6A) is an RNA modification involved in cell physiology and tumor metabolism. It has been observed to affect the evolution of diverse cancers through the regulation of gene expression. Genes associated with m6A are prominent in PCa and are involved in multiple aspects of desmoresistant PCa occurrence, progression, PCa bone metastasis (BM), and treatment resistance. Here, we explore the role of m6A modifications in promoting PCa.

Multidimensional outlook on the pathophysiology of cervical cancer invasion and metastasis

Cervical cancer being one of the primary causes of high mortality rates among women is an area of concern, especially with ineffective treatment strategies. Extensive studies are carried out to understand various aspects of cervical cancer initiation, development and progression; however, invasive cervical squamous cell carcinoma has poor outcomes. Moreover, the advanced stages of cervical cancer may involve lymphatic circulation with a high risk of tumor recurrence at distant metastatic sites. Dysregulation of the cervical microbiome by human papillomavirus (HPV) together with immune response modulation and the occurrence of novel mutations that trigger genomic instability causes malignant transformation at the cervix. In this review, we focus on the major risk factors as well as the functionally altered signaling pathways promoting the transformation of cervical intraepithelial neoplasia into invasive squamous cell carcinoma. We further elucidate genetic and epigenetic variations to highlight the complexity of causal factors of cervical cancer as well as the metastatic potential due to the changes in immune response, epigenetic regulation, DNA repair capacity, and cell cycle progression. Our bioinformatics analysis on metastatic and non-metastatic cervical cancer datasets identified various significantly and differentially expressed genes as well as the downregulation of potential tumor suppressor microRNA miR-28-5p. Thus, a comprehensive understanding of the genomic landscape in invasive and metastatic cervical cancer will help in stratifying the patient groups and designing potential therapeutic strategies.

Phospholysine phosphohistidine inorganic pyrophosphate phosphatase suppresses human esophageal cancer cell growth by inducing mitotic catastrophe through the P27/cyclin A/CDK2 signaling pathway

Esophageal cancer (ESCA) is a global dead malignancy with poor prognosis. However, its underlying molecular mechanism remains to be elucidated. Phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) has been reported as a tumor suppressor in multisystem cancer but its function in ESCA has not been reported. We analyzed LHPP expression between normal and tumor tissues of ESCA patients and performed LHPP overexpression on the ESCA cells KYSE-150 (K150). We did not observe significant differences in the expression level of LHPP between ESCA and normal tissue, and noticed that LHPP expression was not related to ESCA patient survival rate. However, increased expression of LHPP in K150 cells induced mitochondrial dysfunction, inhibited cell proliferation, migration, and cell cycle, and simultaneously increased cell apoptosis. Besides, we found that K150 cells underwent mitotic catastrophe after overexpressing LHPP, which may be regulated through the P27/cyclin A/cdk2 signaling pathway. Although the expression of LHPP may not be related to the progression and prognosis of ESCA, mitotic catastrophe, a new mechanism of tumor suppressor function of LHPP was found after overexpressing LHPP in ESCA cells. DATA AVAILABILITY: The data used to support the findings of this study are included within the article.

LHPP suppresses proliferation, migration, and invasion in hepatocellular carcinoma and pancreatic cancer by inhibiting EGFR signaling pathway

Phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) has been reported to be a new tumor suppressor with a significant inhibitory effect in various cancers. Although LHPP has been repeatedly shown to inhibit the progression of various tumors by inhibiting the phosphorylation of AKT, up to now, the studies on the function and mechanism of LHPP in tumors are insufficient. In this study, LHPP expression was found to be downregulated in both hepatocellular carcinoma (HCC) and pancreatic cancer (PC). Here, we found that LHPP could bind to epidermal growth factor receptor (EGFR) and inhibit its phosphorylation, which thereby inhibited the activation of EGFR downstream pathways ERK, AKT, and STAT3, and then weakening the ability to proliferate, invade, and migrate in HCC and PC. This paper showed a new physiological function of LHPP in inhibiting phosphorylation of EGFR and its potential anti-tumor mechanism and indicated that LHPP was a potential therapeutic target for HCC and PC.

A Comprehensive View of the Cancer-Immunity Cycle (CIC) in HPV-Mediated Cervical Cancer and Prospects for Emerging Therapeutic Opportunities

Cervical cancer (CC) is the fourth most common cancer in women worldwide, with more than 500,000 new cases each year and a mortality rate of around 55%. Over 80% of these deaths occur in developing countries. The most important risk factor for CC is persistent infection by a sexually transmitted virus, the human papillomavirus (HPV). Conventional treatments to eradicate this type of cancer are accompanied by high rates of resistance and a large number of side effects. Hence, it is crucial to devise novel effective therapeutic strategies. In recent years, an increasing number of studies have aimed to develop immunotherapeutic methods for treating cancer. However, these strategies have not proven to be effective enough to combat CC. This means there is a need to investigate immune molecular targets. An adaptive immune response against cancer has been described in seven key stages or steps defined as the cancer-immunity cycle (CIC). The CIC begins with the release of antigens by tumor cells and ends with their destruction by cytotoxic T-cells. In this paper, we discuss several molecular alterations found in each stage of the CIC of CC. In addition, we analyze the evidence discovered, the molecular mechanisms and their relationship with variables such as histological subtype and HPV infection, as well as their potential impact for adopting novel immunotherapeutic approaches.

LHPP Inhibits the Viability, Migration, and Proliferation of PDAC Cells and Significantly Affects the Expression of SDC1 and S100p

INTRODUCTION

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy with a poor response to chemotherapy and an extremely poor prognosis. Recent studies have revealed that phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) can inhibit the growth of various cancers. Therefore, the current study was conducted to investigate the antitumor effects of LHPP in PDAC and to explore its mechanism using proteomics analysis.

METHODS AND RESULTS

Immunohistochemical analysis of clinical samples demonstrated that LHPP expression levels were lower in tumor tissues compared to adjacent nontumor tissues. Moreover, multivariate COX regression analysis showed that LHPP expression level was an independent prognostic factor for the patients with PDAC. Patients with high LHPP expression had a better prognosis. The lentiviral vectors for normal control (NC), LHPP knockdown (KD), and LHPP overexpression (OE) were infected with BxPC-3 and PANC-1 cell lines. Cell counting kit-8 assay, Transwell assay, and flow cytometry analyses showed that LHPP overexpression significantly inhibited the cell viability, migration, and proliferation of BxPC-3 and PANC-1 cells. Moreover, xenograft tumor model demonstrated that LHPP overexpression inhibited xenograft tumor growth in vivo. Subsequently, proteins with significantly altered expression in BxPC-3 cells after lentivirus infection were detected using proteomics analyses. Interestingly, compared to the NC group, the expression of Syndecan 1 (SDC1) was significantly upregulated in the KD group, while that of S100P was significantly downregulated in the OE group.

CONCLUSION

LHPP might emerge as an important target for delaying the advancement of PDAC, thereby providing a novel therapeutic approach for the treatment of PDAC.

Does the LHPP gene share a common biological function in pancancer progression?

Although emerging evidence has revealed that LHPP, a histidine phosphatase protein, suppresses the progression of different cancers, a pan-cancer analysis still remains unavailable. Therefore, we first utilized different bioinformatics tools to explore the tumor inhibitory role of LHPP protein across 33 tumor types based on the TCGA project. Additionally, HGC-27 gastric cancer cells were used to evaluate the biological functions of LHPP after stable transfection with lentiviruses. Consequently, LHPP mRNA and protein expression were down-regulated in the most cancer tissues corresponding to normal tissues. The data showed that patients with higher LHPP performance had a better prognosis of overall survival (OS) and disease-free survival (DFS) in brain glioma and renal carcinoma. In addition, we found that enhancement of LHPP expression attenuated the proliferation, migration and invasion of gastric cancer cells. The expression levels of cell-cycle-related and EMT-related molecules, such as CDK4, CyclinD1, Vimentin and Snail, were clearly reduced. Moreover, a genetic alteration analysis showed that the most frequent mutation types in LHPP protein was amplification. The patients without LHPP mutation showed a better tendency of prognosis in UCEC, STAD and COAD. Cancer-associated fibroblast infiltration was also observed in head and neck squamous cell carcinoma, stomach adenocarcinoma and testicular germ cell tumors. In summary, our pancancer analysis among various tumor types could provide a comprehensive understanding of LHPP biological function in the progression of malignant diseases and promote the development of novel therapeutic targets.

Long noncoding RNA DLGAP1-AS2 promotes tumorigenesis and metastasis by regulating the Trim21/ELOA/LHPP axis in colorectal cancer

Background

Long noncoding RNAs (lncRNAs) have driven research focused on their effects as oncogenes or tumor suppressors involved in carcinogenesis. However, the functions and mechanisms of most lncRNAs in colorectal cancer (CRC) remain unclear.

Methods

The expression of DLGAP1-AS2 was assessed by quantitative RT-PCR in multiple CRC cohorts. The impacts of DLGAP1-AS2 on CRC growth and metastasis were evaluated by a series of in vitro and in vivo assays. Furthermore, the underlying mechanism of DLGAP1-AS2 in CRC was revealed by RNA pull down, RNA immunoprecipitation, RNA sequencing, luciferase assays, chromatin immunoprecipitation, and rescue experiments.

Results

We discovered that DLGAP1-AS2 promoted CRC tumorigenesis and metastasis by physically interacting with Elongin A (ELOA) and inhibiting its protein stability by promoting tripartite motif containing 21 (Trim21)-mediated ubiquitination modification and degradation of ELOA. In particular, we revealed that DLGAP1-AS2 decreases phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) expression by inhibiting ELOA-mediated transcriptional activating of LHPP and thus blocking LHPP-dependent suppression of the AKT signaling pathway. In addition, we also demonstrated that DLGAP1-AS2 was bound and stabilized by cleavage and polyadenylation specificity factor (CPSF2) and cleavage stimulation factor (CSTF3).

Conclusions

The discovery of DLGAP1-AS2, a promising prognostic biomarker, reveals a new dimension into the molecular pathogenesis of CRC and provides a prospective treatment target for this disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12943-022-01675-w.

Screening of Pathogenic Missense Single Nucleotide Variants From LHPP Gene Associated With the Hepatocellular Carcinoma: An In silico Approach

LHPP gene encodes a phospholysine phosphohistidine inorganic pyrophosphate phosphatase, which functions as a tumor-suppressor protein. The tumor suppression by this protein has been confirmed in various cancers, including hepatocellular carcinoma (HCC). LHPP downregulation promotes cell growth and proliferation by modulating the PI3K/AKT signaling pathway. This study identifies potentially deleterious missense single nucleotide variants (SNVs) associated with the LHPP gene using multiple computational tools based on different algorithms. A total of 4 destabilizing mutants are identified as L22P, I212T, G227R, and G236R, from the conserved region of the phosphatase. The 3-dimensional (3D) modeling and structural comparison of variants with the native protein reveals significant structural and conformational variations after mutations, suggesting disruption in the function of phospholysine phosphohistidine inorganic pyrophosphate phosphatase. The identified mutations might, therefore, participate in the cause of HCC.

Tumor suppressor LHPP suppresses cell proliferation and epithelial-mesenchymal transition in hepatocellular carcinoma cell lines

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer in the world with high mortality due to its high potential of metastasis. Epithelial-mesenchymal transition (EMT) plays a key role in the pathogenesis of HCC occurrence and metastasis. Phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) is a novel tumor suppressor. There is little study about LHPP in human HCC development. In the present study, we aimed to investigate the role of LHPP in human HCC cell metastasis. We analyzed the LHPP expression level in human HCC tissues compared with normal tissues in the public database. We detected the mRNA level and protein level of LHPP in transformed liver cell line (LO2) and human HCC cell lines (MHCC-97 H, MHCC-97L, and HepG2). We performed genetic gain and loss of function experiments with LHPP using small interfering RNA (siRNA) and lentivirus infection. Then, we detected that LHPP suppressed proliferation and promoted apoptosis in hepatocellular carcinoma cell lines. Also, we investigated the role of LHPP in the EMT process. Finally, we examined the effect of LHPP on TGF-β-induced EMT. Interestingly, we also found that LHPP expression is positively regulated tumor suppressor p53. Our data showed that LHPP is significantly decreased in the human HCC tissues and human HCC cell lines compared with normal liver tissues and transformed liver cells. Knockdown of LHPP promotes HCC cell proliferation and metastasis, and LHPP expression levels negatively correlate with EMT-related genes. Furthermore, LHPP inhibits TGF-β-induced EMT in HCC cell lines. These studies validate LHPP as a tumor suppressor in liver cancer and provide a new genetic target for HCC diagnosis and treatment.

The histidine phosphatase LHPP: an emerging player in cancer

Cancers continue to have high incidence and mortality rates worldwide. Therefore, cancer control remains the main public health goal. Growing research evidence suggests that phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) plays an important role in inhibiting tumor cell progression. It has been reported in the literature that LHPP is expressed at low levels in tumor tissues and cells and that patients with low LHPP expression have a poorer prognosis. Functional studies have shown that LHPP can inhibit tumor cell proliferation, metastasis, and apoptosis by affecting different target genes. In addition, researchers have used iDPP nanoparticles to deliver LHPP plasmids to treat tumors, demonstrating the great potential of LHPP plasmids for cancer therapy. In our review, we highlight the biological functions and important downstream target genes of LHPP in tumors, providing a theoretical basis for the treatment of human cancers. Although not thoroughly studied in terms of tumor mechanisms, LHPP still represents a promising and effective anticancer drug target.

COVID-19 Pandemic Effects on Cervical Cancer Diagnosis and Management: A Population-Based Study in Romania

The Pap test plays a significant role worldwide in the early diagnosis of and high curability rates for cervical cancer. However, the coronavirus disease 2019 (COVID-19) pandemic necessitated the use of multiple drastic measures to stop the spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, limiting women’s access to essential invasive and non-invasive investigations for cervical cancer diagnosis. Therefore, we aimed to determine the impact the COVID-19 pandemic had on cancer diagnosis and management in western Romania. A retrospective study design allowed us to compare the last 24 months of the pre-pandemic period with the first 24 months of the COVID-19 pandemic to determine the change in volume of cervical screening tests, the number of newly diagnosed cases and their severity, and the access to cancer care. A drastic 75.5% decrease in the volume of tests was observed in April 2020 during the first lockdown, after which the volume of cases decreased by up to 36.1% in December 2021. The total volume loss of tests during the first 24 months of the pandemic was 49.9%. The percentage of late-stage cervical cancers (III–IV) rose by 17%, while the number of newly diagnosed cancers in our outpatient clinic was significantly lower than the baseline, with a 45% drop. The access to cancer care was negatively influenced, with 9.2% more patients waiting longer to receive test results over four weeks, while taking longer to seek cancer care after diagnosis (6.4 months vs. 4.1 months pre-pandemic) and missing significantly more appointments. The COVID-19 pandemic had a significantly negative impact on cervical cancer diagnosis and management during the first 24 months compared with the same period before the pandemic. Although the numbers are now recovering, there is still a big gap, meaning that many cervical cancer cases were potentially missed. We recommend further interventions to reduce the gap between the pre-pandemic and pandemic period.

As a Novel Tumor Suppressor, LHPP Promotes Apoptosis by Inhibiting the PI3K/AKT Signaling Pathway in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) refers to the malignant tumor of the head and neck with a highest morbidity. It exhibits a poor prognosis and unsatisfactory treatment partially attributed to delayed diagnosis. As indicated from existing reports, the protein histidine phosphatase LHPP acts as a vital factor in tumorigenesis in liver, lung, bladder, breast and pancreatic tumor tissues. Thus far, the functional mechanism of LHPP in OSCC remains unclear. DGE analysis, OSCC cell lines and OSCC cases were found that LHPP was down-regulated in OSCC tissues and cells compared with that in normal oral mucosa tissues and cells, and was closely related to OSCC differentiation. Cell counting Kit 8 test, EdU proliferation test, scratches test, invasion test, monoclonal formation test, mouse xenograft tumor model, HE staining and immunohistochemistry showed that LHPP inhibited OSCC growth, proliferation and migration in vivo and in vitro. GO and KEGG enrichment analysis, LHPP transcription factor analysis and flow cytometry found that LHPP promotes the apoptosis of OSCC by decreasing the transcriptional activity of p-PI3K and p-Akt. Finally, our results suggested that LHPP inhibited the progression of OSCC through the PI3K/AKT signaling pathway, indicating that LHPP may be a new target for the treatment of OSCC.

circPTEN suppresses colorectal cancer progression through regulating PTEN/AKT pathway

Recently, circular RNAs (circRNAs) have attracted growing attention due to their pivotal roles in the complicated cellular processes of diverse human malignancies, including colorectal cancer (CRC). Phosphatase and tensin homolog (PTEN) is known as a typical tumor-suppressing gene. Nevertheless, limited investigation on the function of circRNAs generated from PTEN has been undertaken. In this research, hsa_circ_0094343 (circPTEN) was found to display low expression in CRC tissues and cells. CircPTEN is characterized with high stability due to its circular structure. Upregulation of circPTEN suppressed CRC cell proliferation, migration, and invasion but facilitated apoptosis. Data from mechanism assays revealed that circPTEN could elevate PTEN expression through sequestering microRNA-4470 (miR-4470) in CRC cells. Further, circPTEN was validated to inhibit K63-linked ubiquitination of protein kinase B (AKT) and AKT phosphorylation at Thr-308 and Ser-473 by competitively binding with tumor necrosis factor (TNF)-receptor-associated factor 6 (TRAF6). Moreover, the results of rescue assays indicated that the suppressive effect of circPTEN on CRC progression could be totally reversed by overexpression of insulin like growth factor 1 (IGF-1) or partially reversed by knockdown of PTEN. To conclude, circPTEN suppresses CRC progression via regulation of PTEN/AKT pathway.

LHPP suppresses colorectal cancer cell migration and invasion in vitro and in vivo by inhibiting Smad3 phosphorylation in the TGF-β pathway

The roles of phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) in tumorigenesis have been recently proven in hepatocellular carcinoma (HCC), cervical, pancreatic, bladder, and thyroid cancers. Previous research demonstrated that LHPP repressed cell proliferation and growth by inactivating the phosphatidylinositol 3-kinase/AKT signaling pathway in vitro and in vivo. However, the functions and potential mechanisms of LHPP as a tumor suppressor in colorectal cancer (CRC) metastasis are still unknown. Consequently, the Transwell assay and xenograft nude model showed that LHPP inhibited migration and invasion of CRC cells in vitro and in vivo, respectively. The expression of total and nuclear epithelial-to-mesenchymal transition (EMT)-related proteins were significantly reduced after LHPP upregulation. Human Gene Expression Array and IPA (Ingenuity Pathway Analysis) commercial software were applied to identify differentially expressed genes (DEGs) and potential cell signaling pathways. A total of 330 different genes were observed, including 177 upregulated genes and 153 downregulated genes. Bioinformatics analysis suggested that the transforming growth factor-β (TGF-β) signaling pathway was highly inactivated in this study. Then, Smad3 phosphorylation was apparently decreased, whereas Smad7 expression was markedly enhanced after upregulating LHPP expression. These results were proven once again after TGF-β1 stimulation. Furthermore, a specific inhibitor of Smad3 phosphorylation (SIS3) was applied to verify that LHPP repressed EMT of cancer cells by attenuating TGF-β/Smad signaling. The results suggested that suppression of the TGF-β/Smad signaling pathway by LHPP overexpression could be abolished by SIS3.

Downregulation of LHPP Expression Associated with AFP Acts as a Good Prognostic Factor in Human Hepatocellular Carcinoma

Background

Phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) serves as a tumor suppressor in hepatocellular carcinoma (HCC), but the correlation between the expression of LHPP and the clinical parameters of oncogenic progression is still not well defined. This study is to reveal the correlation between the expression of LHPP in HCC and their clinical parameters.

Methods

Immunohistochemical analysis was used to assess the correlation between the expression of LHPP and the clinical parameters of HCC. Expressions of LHPP in HCC tissues and cultured HCC cells were detected by Western blot and quantitative real-time polymerase chain reaction (qRT-PCR). LHPP, gamma-glutamyl transferase (GGT), and α-fetoprotein (AFP) expression levels in blood or HCC tissues were detected by enzyme-linked immunosorbent assay (ELISA). The Spearman rank correlation coefficient was used to evaluate the correlation of the expression of LHPP and the clinical index of HCC. Correlation of survival and expression of LHPP were analyzed using the Kaplan-Meier method and the log-rank test.

Results

Expressions of LHPP in HCC tissues were significantly downregulated than their paired adjacent normal tissues. A significant positive correlation was found between the cytoplasm and nuclear expression of LHPP in both HCC and their paired adjacent normal tissues. The expression of LHPP negatively correlated with the levels of GGT in the cytoplasm of adjacent tissues and with the AFP level in the nucleus of HCC cells. Relative levels of LHPP in HCC tissues were markedly lower than those of the paired adjacent normal tissues. Relative levels of LHPP in LO-2 cells were higher than those of HepG2, BEL-7404, and SMMC-7721 cell lines. The overall survival and DSF survival of patients with the high expression of LHPP were much higher than those with the low expression of LHPP in paired adjacent normal tissue.

Conclusions

LHPP is associated with the AFP level and acts as a good prognostic factor in HCC.

Oncogenic role of ALX3 in cervical cancer cells through KDM2B-mediated histone demethylation of CDC25A

Background

Cell division cycle 25A (CDC25A) is a well-recognized regulator of cell cycle progression and is involved in cancer development. This work focused on the function of CDC25A in cervical cancer cell growth and the molecules involved.

Methods

A GEO dataset GSE63514 comprising data of cervical squamous cell carcinoma (CSCC) tissues was used to screen the aberrantly expressed genes in cervical cancer. The CDC25A expression in cancer and normal tissues was predicted in the GEPIA database and that in CSCC and normal cells was determined by RT-qPCR and western blot assays. Downregulation of CDC25A was introduced in CSCC cells to explore its function in cell growth and the cell cycle progression. The potential regulators of CDC25A activity and the possible involved signaling were explored.

Results

CDC25A was predicted to be overexpressed in CSCC, and high expression of CDC25A was observed in CSCC cells. Downregulation of CDC25A in ME180 and C33A cells reduced cell proliferation and blocked cell cycle progression, and it increased cell apoptosis. ALX3 was a positive regulator of CDC25A through transcription promotion. It recruited a histone demethylase, lysine demethylase 2B (KDM2B), to the CDC25A promoter, which enhanced CDC25A expression through demethylation of H3k4me3. Overexpression of ALX3 in cells blocked the inhibitory effects of CDC25A silencing. CDC25A was found as a positive regulator of the PI3K/Akt signaling pathway.

Conclusion

This study suggested that the ALX3 increased CDC25A expression through KDM2B-mediated demethylation of H3K4me3, which induced proliferation and cell cycle progression of cervical cancer cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08552-7.

HDAC6 suppresses microRNA-199a transcription and augments HPV-positive cervical cancer progression through Wnt5a upregulation

High-risk human papillomavirus (HR-HPV) infection is a major risk factor for the initiation and progression of cervical cancer (CC). This study aimed to explore the role of histone deacetylase 6 (HDAC6) in HPV-positive CC and the molecules implicated. Differentially expressed genes between HPV-positive and HPV-negative tissues, and differentially expressed microRNAs (miRNAs) in cells after HDAC6 downregulation were identified using microarray analyses. The expression profiles of HDAC6 and miR-199a and their cellular functions were investigated via loss-of-function studies. Xenograft tumors were induced in mice for in vivo studies. HDAC6 and Wnt5a were highly expressed, whereas miR-199a was poorly expressed in HPV-positive CC tissues. Downregulation of HDAC6 reduced proliferation, migration, invasion, and resistance to apoptosis of HPV-positive CC cells. HDAC6 suppressed the transcription of miR-199a, and miR-199a targeted Wnt5a to inactivate the Wnt signaling pathway. Further downregulation of miR-199a blocked the inhibitory effect of HDAC6 silencing on CC cell growth both in vivo and in vitro, whereas further artificial inhibition of Wnt5a inactivated Wnt signaling and blocked the malignant behaviors of CC cells. This study showed that HDAC6 suppresses the transcription of miR-199a and enhances the progression of HPV-positive cervical cancer through upregulation of Wnt5a.

LHPP suppresses proliferation, migration, and invasion and promotes apoptosis in pancreatic cancer

Pancreatic cancer (PaCa) is a common malignant tumor of the digestive system with poor prognosis and no ideal treatment for inoperable patients, which is partly due to delayed diagnoses. It is recently reported that the protein histidine phosphatase LHPP is a tumor suppressor in hepatocellular carcinoma, cervical cancer, and bladder cancer. So far, there is no study on the expression level of LHPP in PaCa, and its mechanism of action on tumors is unclear. In this experiment, LHPP expression was lower in cancer tissues than that in normal pancreatic tissue, and clinicopathological results showed that LHPP expression was correlated with the degree of differentiation and lymphatic metastasis of pancreatic carcinoma. The biological characteristics of LHPP in PaCa cells were examined by the cell counting kit-8 assay, transwell assay, and monoclonal formation test. The inhibitory mechanism of LHPP in PaCa cells was determined using Western blotting and flow cytometry. The results showed that LHPP restrained PaCa cell proliferation, migration, and invasion. Increased LHPP expression promoted the apoptosis of PaCa cells through higher activation of cleaved-PARP and cleaved-Casp3 and lower activation of cIAP1. Importantly, the increase in LHPP enhanced PTEN expression and decreased the phosphorylated AKT level. Moreover, LHPP-induced apoptosis was diminished by SC79 (AKT activator) in PaCa cells. In conclusion, LHPP blocks proliferation, migration, and invasion and enhances apoptosis in PaCa cells through the PTEN/AKT signaling pathway.

LHPP-Mediated Histidine Dephosphorylation Suppresses the Self-Renewal of Mouse Embryonic Stem Cells

Self-renewal of embryonic stem cells (ESCs) is orchestrated by a vast number of genes at the transcriptional and translational levels. However, the molecular mechanisms of post-translational regulatory factors in ESC self-renewal remain unclear. Histidine phosphorylation, also known as hidden phosphorylation, cannot be detected by conventional experimental methods. A recent study defined phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) as a histidine phosphatase, which regulates various biological behaviors in cells via histidine dephosphorylation. In this study, the doxycycline (DOX)-induced hLHPP-overexpressing mouse ESCs and mouse LHPP silenced mESCs were constructed. Quantitative polymerase chain reaction (qPCR), western blotting analysis, immunofluorescence, Flow cytometry, colony formation assays, alkaline phosphatase (AP) and bromodeoxyuridine (Brdu) staining were performed. We found that the histidine phosphorylation level was strikingly reduced following LHPP overexpression. Besides, the expression of Oct4 and Lefty1, indispensable genes in the process of ESCs self-renewal, was significantly down-regulated, while markers related to the differentiation were markedly elevated. Moreover, LHPP-mediated histidine dephosphorylation induced G_0/G₁ phase arrest in mESCs, suggesting LHPP was implicated in cell proliferation and cell cycle. Conversely, silencing of Lhpp promoted the self-renewal of mESCs and reversed the RA induced increased expression of genes associated with differentiation. Mechanistically, our findings suggested that the enzymatic active site of LHPP was the cysteine residue at position 226, not 53. LHPP-mediated histidine dephosphorylation lowered the expression levels of β-catenin and the cell cycle-related genes CDK4 and CyclinD1, while it up-regulated the cell cycle suppressor genes P21 and P27. Taken together, our findings reveal that LHPP-mediated histidine dephosphorylation plays a role in the self-renewal of ESCs. LHPP-mediated histidine dephosphorylation inhibited the self-renewal of ESCs by negatively regulating the Wnt/β-catenin pathway and downstream cell cycle-related genes, providing a new perspective and regulatory target for ESCs self-renewal.

LHPP suppresses tumorigenesis of intrahepatic cholangiocarcinoma by inhibiting the TGFβ/smad signaling pathway

Phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP), a histidine phosphatase, plays an important role in tumor progression and metastasis as a tumor suppressor. Here, we investigate the effect of LHPP in intrahepatic cholangiocarcinoma (ICC). We discovered that LHPP was downregulated in tumor tissues and low levels of LHPP predicted poor survival. LHPP inhibited ICC cell growth, cell invasion and epithelial-mesenchymal transition (EMT) in vitro and in vivo. Mechanically, LHPP deactivated transforming growth factor‑beta (TGFβ) signaling pathway, and low level LHPP upregulated the expression of TGFβ and phosphorylation of smad2/3. Moreover, inhibition of this pathway reversed the biofunction of LHPP. In summary, these findings demonstrated that LHPP suppressed ICC through inhibiting the activation of TGFβ/smad signaling. Our results indicated that LHPP is a potential therapeutic target in ICC.

Purpurin binding interacts with LHPP protein that inhibits PI3K/AKT phosphorylation and induces apoptosis in colon cancer cells HCT-116

Colorectal cancer (CRC) is the leading type of diagnosed cancer; globally, it resides in the fourth-leading origin of cancer-interrelated mortality in the globe. The treatment strategies were chemotherapy and potent radiotherapy. Although chemotherapy treatment can eliminate tumor cells, it remains with unnecessary toxic effects in cancer patients. Therefore, the identification of natural-based compounds, which have selectively inhibiting target proteins with limited toxicity that can facilitate the therapeutic approaches against CRC. In this existing approach, which highlights the binding efficacy of our anthraquinone compound, purpurin against phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) protein restrains the CRC cell growth by inhibiting phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT), cell proliferation, and inducing apoptosis signaling. Primarily, purpurin (36 μM) exposed to HCT-116 cells and incubated for 24 and 48 h could induce reactive oxygen species production, subsequently alter mitochondrion membrane, and increase the apoptotic cells in HCT-116. LHPP, a kind of histidine phosphatase protein, has been considered as a tumor suppressor in numerous carcinomas. However, purpurin-mediated LHPP proteins and its associated molecular events in CRC remain unclear. In our docking studies revealed that purpurin has been strongly interacts with LHPP via hydrophobic and hydrophilic binding interaction. Western blot results confirmed that purpurin enhances the expression of LHPP protein, thereby inhibits the expression of phosphorylated-PI3K/AKT, EGFR, cyclin-D1, PCNA in HCT-116 cells. Moreover, purpurin induces messenger RNA expression of apoptotic genes (Bax, CASP-9, and CASP-3) in HCT-116 cells. Thus, we conclude that purpurin could be a natural and useful compound, which inhibits the growth of CRC cells through the activation of LHPP proteins.

Ultrasound-Targeted Microbubble Destruction Enhances the Inhibitive Efficacy of miR-21 Silencing in HeLa Cells

BACKGROUND Previous studies have shown that miR-21 upregulation is related to the aggressive development of cervical cancer. Ultrasound-targeted microbubble destruction (UTMD) is a method that increases the absorption of targeted genes or drugs by cells. We focus on the role of UTMD-mediated miR-21 transfection in HeLa cells, a cervical cancer cell line. MATERIAL AND METHODS The effects of different ultrasound intensities on the transfection efficiency of miR-21-enhanced green fluorescent protein (EGFP) and miR-21 inhibitor-EGFP plasmids were determined by flow cytometry. The effects of UTMD-mediated miR-21 transfection on HeLa cell proliferation, apoptosis, migration, and invasion were measured by CCK-8, flow cytometry, wound healing experiments, and transwell migration assay, respectively. Western blot and real-time quantitative PCR were used to detect the expression of tumor-related genes. RESULTS When the ultrasound intensity was 1.5 W/cm², the miR-21 plasmid had the highest transfection efficiency. Exogenous miR-21 promoted cell proliferation, migration, and invasion, and inhibited cell apoptosis in HeLa cells. Treatment of cells with UTMD further enhanced the effects of miR-21-EGFP and miR-21 inhibitor-EGFP. In addition, miR-21 overexpression significantly increased the expression of p-Akt, Akt, Bcl-2, Wnt, ß-catenin, matrix metalloprotein-9 (MMP-9), and epidermal growth factor (EGFR) levels, and decreased Bax expression. The regulatory role of miR-21 inhibitor-EGFP was opposite to that of miR-21-EGFP. After UTMD, miR-21-EGFP and miR-21 inhibitor-EGFP had more significant regulatory effects on these genes. CONCLUSIONS Our research revealed that an ultrasound intensity of 1.5 W/cm² is the best parameter for miR-21 transfection. UTMD can enhance the biological function of miR-21 in HeLa cells, and alter the effect of miR-21 on apoptosis, metastasis, and phosphorylation genes.

Prognostic Correlation of Glycolysis-Related Gene Signature in Patients with Laryngeal Cancer

BACKGROUND

Aerobic glycolysis is one of the metabolic characteristics of tumor cells, which is regulated by many genes. The aim of our study was to construct glycolysis-related gene signature to accurately predict the prognosis of laryngeal cancer (LC) patients.

METHODS

We analyzed the mRNA expression profiles of LC patients from The Cancer Genome Atlas (TCGA). Eleven glycolysis-related gene sets were analyzed by gene set enrichment analysis (GSEA). In order to acquire the gene signature related to prognosis, we used univariate and multivariate Cox regression analysis.

RESULTS

We confirmed that a gene signature composed of two genes (STC2, LHPP) can predict the overall survival (OS) of patients with LC. Based on each patient's risk score, we found that the survival results of patients in the high-risk group were significantly lower than those in the low-risk group (log-rank test P-value=0.002). Multivariate Cox regression analysis confirmed that gene signature could independently predict OS in LC patients (HR = 1.981, 95% CI 1.446-2.714 P<0.001). In addition, a nomogram including the age, sex, grade and risk score was constructed. The nomogram demonstrated good accuracy for OS prediction, with a C-index of 0.752.

CONCLUSION

The glycolysis-related two-gene risk score model could be used as a biomarker for LC prognosis.

The long intergenic noncoding RNA GAS5 reduces cisplatin-resistance in non-small cell lung cancer through the miR-217/LHPP axis

Long noncoding RNAs (lncRNAs) are known to exert their effects to tumor progression. In this study, the role of the lncRNA GAS5 (growth arrest specific 5) was confirmed in reducing non-small cell lung cancer (NSCLC) cisplatin (DDP) resistance. In NSCLC tissue samples, GAS5 expression decreased significantly. Low GAS5 levels were positively correlated with NSCLC characteristics including TNM, tumor size and lymphatic metastasis. Functionally, GAS5 significantly reduced NSCLC/DDP cell migration, invasion and epithelial-mesenchymal transition (EMT) progression in vitro. In vivo, GAS5 upregulation inhibited remarkably NSCLC/DDP cell tumor growth. Mechanism analysis suggested that GAS5 was a molecular sponge of miR-217, inhibiting the expression of phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP). In conclusion, this study reveals that the GAS5/miR-217/LHPP pathway reduces NSCLC cisplatin resistance and that LHPP may serve as a potential therapeutic target for NSCLC cisplatin resistance.

LHPP exerts a tumor-inhibiting role in glioblastoma via the downregulation of Akt and Wnt/β-catenin signaling

Phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) has been recently identified as a novel inhibitor of multiple tumors; however, its role in glioblastoma (GBM) has not been investigated. This study aimed to evaluate whether LHPP exerts a potential tumor-inhibiting role in GBM. Compared with that in normal tissues, LHPP expression was lower in GBM tissues and various GBM cell lines. LHPP up-regulation in GBM cells markedly reduced their proliferation and invasion, and its knockdown had an oncogenic effect on these cells. Further studies revealed that overexpressed LHPP decreased the levels of Akt and glycogen synthase-3β phosphorylation and down-regulated Wnt/β-catenin signaling. By contrast, LHPP knockdown produced opposite effects. Akt suppression markedly abrogated the activation of Wnt/β-catenin signaling induced by LHPP knockdown. The reactivation of Wnt/β-catenin signaling partially reversed the inhibition of tumor growth in GBM mediated by LHPP overexpression. In addition, LHPP overexpression markedly retarded the tumorigenesis of GBM cells in vivo. These findings revealed that LHPP acts a potential inhibitor of tumor growth in GBM, and its overexpression represses GBM proliferation and invasion by down-regulating Akt and Wnt/β-catenin signaling. This work highlights the crucial role of LHPP in GBM progression and suggests its potential as an anticancer target for the treatment of this disease.

Histone Demethylase KDM3A Promotes Cervical Cancer Malignancy Through the ETS1/KIF14/Hedgehog Axis

Background

Lysine demethylase 3A (KDM3A) has been increasingly recognized as an important epigenetic regulator involved in cancer development. This study aims to explore the relevance of KDM3A to cervical cancer (CC) progression and the molecules involved.

Materials and Methods

Tumor and the adjacent tissues from CC patients were collected. KDM3A expression in tissues and CC cell lines and its correlation with the survival and prognosis of patients were determined. Malignant potentials of CC cells and the angiogenesis ability of HUVECs were measured to evaluate the function of KDM3A on CC progression. The interactions among KDM3A, H3K9me2 and ETS1, and the binding between ETS1 and KIF14 were validated through ChIP and luciferase assays. Altered expression of ETS1 and KIF14 was introduced to explore their roles in CC development.

Results

KDM3A was abundantly expressed in CC tissues and cells and linked to dismal prognosis of CC patients. Knockdown of KDM3A suppressed malignant behaviors of CC cells. KDM3A was found to increase ETS1 expression through the demethylation of H3K9me2. Overexpression of ETS1 blocked the inhibiting roles of sh-KDM3A. ETS1 could bind to the promoter region of KIF14 to trigger its transcription. Overexpression ofKIF14aggravated the malignant behaviors of CC cells and the angiogenesis ability of HUVECs, and it activated the Hedgehog signaling pathway. Artificial activation of Hedgehog by Sag1.5 diminished the effects of sh-KDM3A. These changes were reproduced in vivo.

Conclusion

This study evidenced that KDM3A promotes ETS1-mediated KIF14 transcription to promote CC progression with the involvement of the Hedgehog activation.

Apigenin 7-O-glucoside promotes cell apoptosis through the PTEN/PI3K/AKT pathway and inhibits cell migration in cervical cancer HeLa cells

Epidemiologic evidence promote the inclusion of flavones in diet due to their inhibitory effects on certain types of cancers, particularly in women. Among the naturally occurring plant flavonoids, Apigenin 7-O-glucoside (AGL) is endowed with anti-inflammatory, anti-oxidant, and anti-cancer activities. However, its mechanism of action on cervical cancer, the fourth largest cancer in women, has not yet been clarified. In the current study, we have determined the effect of AGL on human cervical cancer cells and studied its molecular mechanism against cervical cancer. The results showed that AGL inhibited the proliferation of HeLa cells (IC₅₀ was 47.26 μM at 48 h) by inducing apoptosis. Furthermore, AGL treatment caused G0/G1 phase arrest, reduced mitochondrial membrane potential (MMP), and upgraded intracellular ROS production. AGL could promote the release of cytochrome c by regulating Bcl-2 family proteins, and then activated caspase 9/3 to promote cell apoptosis. Moreover, AGL treatment promoted the expression of p16 INK4A, while inhibited the expression of Cyclin A/D/E and CDK2/6. At the same time in HeLa cells treated with AGL, the PTEN/PI3K/AKT pathway was inhibited in a concentration-dependent manner, and cell migration was also impeded correspondingly through the matrix metalloproteinase 2 and 9. Our study may provide a new research direction for harnessing the novel natural compounds in cervical cancer treatment.

YTHDF2 mediates the mRNA degradation of the tumor suppressors to induce AKT phosphorylation in N6-methyladenosine-dependent way in prostate cancer

Background

N6-methyladenosine (m⁶A) is the most abundant modification in mRNA of humans. Emerging evidence has supported the fact that m⁶A is comprehensively involved in various diseases especially cancers. As a crucial reader, YTHDF2 usually mediates the degradation of m⁶A-modified mRNAs in m⁶A-dependent way. However, the function and mechanisms of m⁶A especially YTHDF2 in prostate cancer (PCa) still remain elusive.

Methods

To investigate the functions and mechanisms of YTHDF2 in PCa, in vitro, in vivo biofunctional assays and epigenetics experiments were performed. Endogenous expression silencing of YTHDF2 and METTL3 was established with lentivirus-based shRNA technique. Colony formation, flow cytometry and trans-well assays were performed for cell function identifications. Subcutaneous xenografts and metastatic mice models were combined with in vivo imaging system to investigate the phenotypes when knocking down YTHDF2 and METTL3. m⁶A RNA immunoprecipitation (MeRIP) sequencing, mRNA sequencing, RIP-RT-qPCR and bioinformatics analysis were mainly used to screen and validate the direct common targets of YTHDF2 and METTL3. In addition, TCGA database was also used to analyze the expression pattern of YTHDF2, METTL3 and the common target LHPP in PCa, and their correlation with clinical prognosis.

Results

The upregulated YTHDF2 and METTL3 in PCa predicted a worse overall survival rate. Knocking down YTHDF2 or METTL3 markedly inhibited the proliferation and migration of PCa in vivo and in vitro. LHPP and NKX3–1 were identified as the direct targets of both YTHDF2 and METTL3. YTHDF2 directly bound to the m⁶A modification sites of LHPP and NKX3–1 to mediate the mRNA degradation. Knock-down of YTHDF2 or METTL3 significantly induced the expression of LHPP and NKX3–1 at both mRNA and protein level with inhibited phosphorylated AKT. Overexpression of LHPP and NKX3–1 presented the consistent phenotypes and AKT phosphorylation inhibition with knock-down of YTHDF2 or METTL3. Phosphorylated AKT was consequently confirmed as the downstream of METTL3/YTHDF2/LHPP/NKX3–1 to induce tumor proliferation and migration.

Conclusion

We propose a novel regulatory mechanism in which YTHDF2 mediates the mRNA degradation of the tumor suppressors LHPP and NKX3–1 in m⁶A-dependent way to regulate AKT phosphorylation-induced tumor progression in prostate cancer. We hope our findings may provide new concepts of PCa biology.

Combining free energy calculations with tailored enzyme activity assays to elucidate substrate binding of a phospho-lysine phosphatase

Studying enzymes that are involved in the regulation of dynamic post-translational modifications (PTMs) is of key importance in proteomics research. Such investigations can be particularly challenging when the modification itself is intrinsically labile. In this article, we elucidate the enzymatic activity of Phospholysine Phosphohistidine Inorganic Pyrophosphate Phosphatase (LHPP) towards different O- and N-phosphorylated peptides by a combined experimental and computational approach. LHPP has been previously described to hydrolyze the phosphoramidate bonds in different small molecule substrates, including phosphorylated lysine (pLys). Taking the instability of the phosphoramidate bond into account, we conducted a carefully adjusted enzymatic assay with various pLys pentapeptides to confirm enzymatic phosphatase activity with LHPP. Molecular docking was employed to explore possible binding poses of the substrates in complex with the enzyme. Molecular dynamics based free energy calculations, which are unique in their accuracy and solid theoretical basis, were further applied to predict relative binding affinity of different substrates. Comparison of simulations with experiments clearly suggested a distinct binding motif of pLys peptides as well as a very narrow promiscuity of LHPP. We believe this integrated approach can be widely adopted to study the structure and interaction of poorly characterized enzyme-substrate complexes, in particular with synthetically challenging or labile substrates.

The Significance of Circular RNA DDX17 in Prostate Cancer

Circular RNA DDX17 (circDDX17) has been demonstrated as a tumor suppressor in colorectal cancer. However, mechanisms underlying circDDX17 effects in cases of prostate cancer (PCa) are not well understood. Thus, herein, we determined measures of circDDX17 expression by use of the TCGA database. Expression of circDDX17 in prostate cancer-afflicted tissue samples was determined by qRT-PCR. Functionally, circDDX17 induced remarkable inhibition of cell colonizing ability, invasion, and epithelial-mesenchymal transition (EMT) progression in vitro. Mechanistically, dual-luciferase reporter assays, RNA immunoprecipitation, and RNA pull-down experiments helped verify interactions between circDDX17 and miR-346. Low expression of circDDX17 occurred in TCGA PCa samples. Furthermore, circDDX17 expression was downregulated significantly in PCa. These results suggested that circDDX17 suppressed PC cell mobility, proliferation, and invasion. Mechanistic experiments indicated that circDDX17 might serve as a ceRNA of miR-346 to relieve repressive effects of miR-346 upon phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP). LHPP expression itself was downregulated in TCGA PCa samples. Overall, our findings indicated that the circDDX17/miR-346/LHPP pathway inhibited the progression of prostate cancer and that circDDX17 may be a new potential therapeutic or diagnostic target for treating and diagnosing prostate cancer. As our study also demonstrated for the first time that LHPP might act as an anticancer gene in prostate cancer, the findings could have wide-ranging implications for the treatment of this affliction.

Influence of Genetic Variance on Biomarker Levels After Occupational Exposure to 1,6-Hexamethylene Diisocyanate Monomer and 1,6-Hexamethylene Diisocyanate Isocyanurate

We evaluated the impact of genetic variance on biomarker levels in a population of workers in the automotive repair and refinishing industry who were exposed to respiratory sensitizers 1,6-hexamethylene diisocyanate (HDI) monomer and one of its trimers, HDI isocyanurate. The exposures and respective urine and plasma biomarkers 1,6-diaminohexane (HDA) and trisaminohexyl isocyanurate (TAHI) were measured in 33 workers; and genome-wide microarrays (Affymetrix 6.0) were used to genotype the workers' single-nucleotide polymorphisms (SNPs). Linear mixed model analyses have indicated that interindividual variations in both inhalation and skin exposures influenced these biomarker levels. Using exposure values as covariates and a false discovery rate < 0.10 to assess statistical significance, we observed that seven SNPs were associated with HDA in plasma, five were associated with HDA in urine, none reached significance for TAHI in plasma, and eight were associated with TAHI levels in urine. The different genotypes for the 20 significant SNPs accounted for 4- to 16-fold changes observed in biomarker levels. Associated gene functions include transcription regulation, calcium ion transport, vascular morphogenesis, and transforming growth factor beta signaling pathway, which may impact toxicokinetics indirectly by altering inflammation levels. Additionally, in an expanded analysis using a minor allele cutoff of 0.05 instead of 0.10, there were biomarker-associated SNPs within three genes that have been associated with isocyanate-induced asthma: ALK, DOCK2, and LHPP. We demonstrate that genetic variance impacts the biomarker levels in workers exposed to HDI monomer and HDI isocyanurate and that genetics can be used to refine exposure predictions in small cohorts when quantitative personal exposure and biomarker measurements are included in the models.

NME/NM23/NDPK and Histidine Phosphorylation

The NME (Non-metastatic) family members, also known as NDPKs (nucleoside diphosphate kinases), were originally identified and studied for their nucleoside diphosphate kinase activities. This family of kinases is extremely well conserved through evolution, being found in prokaryotes and eukaryotes, but also diverges enough to create a range of complexity, with homologous members having distinct functions in cells. In addition to nucleoside diphosphate kinase activity, some family members are reported to possess protein-histidine kinase activity, which, because of the lability of phosphohistidine, has been difficult to study due to the experimental challenges and lack of molecular tools. However, over the past few years, new methods to investigate this unstable modification and histidine kinase activity have been reported and scientific interest in this area is growing rapidly. This review presents a global overview of our current knowledge of the NME family and histidine phosphorylation, highlighting the underappreciated protein-histidine kinase activity of NME family members, specifically in human cells. In parallel, information about the structural and functional aspects of the NME family, and the knowns and unknowns of histidine kinase involvement in cell signaling are summarized.

LHPP inhibits hepatocellular carcinoma cell growth and metastasis

Hepatocellular carcinoma (HCC) has a poor prognosis, owing to its high potential for growth and metastasis. In this study, we aimed to investigate the roles of Phospholysine Phosphohistidine Inorganic Pyrophosphate Phosphatase (LHPP)in human HCCcell growth and metastasis. We analyzed the LHPP expression level in human HCC tissues paired normal tissues in the Oncomine database, and assessed the relationship between the LHPP expression levels with HCC patient's overall survival and the prognostic value of LHPP in human HCC by Kaplan-Meier survival analysis. Real-time PCR and Western Blot were used to examine the expression levels of LHPP in normal liver cell line (LO2) and human HCC cell lines (SMCC-7721, HepG2, Huh7, MHCC-97 H, and LM3). Through lentivirus infection, we established human HCC stable cell lines (Huh7 and LM3) overexpressing LHPP. Then, we detected these cell viability, colony , and invasion. Subsequently, we performed the gene set enrichment analysis (GSEA) for the RNA-seq data of HCC patients from TCGA. Finally, we examined the expression level of several oncogenes, including CCNB1, PKM2, MMP7, and MMP9, in these cells via real-time PCR assay. Here, we found thatLHPPis significantly downregulated in the human HCC tissues paired normal tissues. Furthermore, the high expression level of LHPP is associated with better clinical outcomes in human HCC. Overexpression of LHPPinhibitscell growth and metastasis in human HCC cells, and LHPP expression levels negatively correlate with cell cycle and metastasis in HCC tissues. Moreover, the level of LHPP is negatively correlated with CCNB1, PKM2, MMP7, and MMP9 in human HCC cells and HCC tissues. These findings highlight a novel tumor suppressor in human HCC growth and metastasis, and provide a promising diagnostic and prognostic factor for humanHCC.

LHPP inhibits cell growth and migration and triggers autophagy in papillary thyroid cancer by regulating the AKT/AMPK/mTOR signaling pathway

In recent decades, the incidence rate of papillary thyroid carcinoma (PTC) has been rapidly increasing. However, the molecular mechanism of the physiological and pathological processes of PTC is still largely unknown. Phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) is a tumor suppressor and exerts anti-tumor effect in several human cancers, while the role and underlying mechanism of LHPP in PTC remain vague. In this study, we firstly evaluated the roles of LHPP in PTC and explored its underlying mechanism. Using clinical tissue samples, we detected the level of LHPP in PTC tissues and in matched adjacent normal tissues. Lower level of LHPP was found in PTC tissues than in matched adjacent normal tissues. Similar LHPP expression pattern was found in PTC cell lines when compared with that in normal human thyroid follicular epithelial cells. Then, we over-expressed LHPP in three PTC cell lines and results showed that ectopic LHPP expression consistently reduced cell viability, proliferation, and migration and triggered cell autophagy. Furthermore, over-expression of LHPP inhibited the activation of the AKT/mTOR pathway and promoted the AMPK signaling pathway. In addition, the activation of AKT/mTOR and inhibition of AMPK signaling pathways restored the role of ectopic LHPP expression in PTC cell lines, indicating that LHPP exerts its anti-tumor activity through regulating the AKT/AMPK/mTOR pathway. Ultimately, we illustrated that ectopic LHPP expression inhibited PTC tumor growth in vivo. In conclusion, we revealed that LHPP has an anti-tumor effect in PTC and indicated that LHPP might serve as an effective diagnostic and therapeutic target for PTC.

Icariside II suppresses cervical cancer cell migration through JNK modulated matrix metalloproteinase-2/9 inhibition in vitro and in vivo

Metastasis contributes a lot to cervical cancer high mortality rate. Icariside II is the principal component of Epimedium brevicornum Maxim and the major functional part to its therapeutic properties. However, the effects and mechanisms of Icariside II on cervical cancer metastasis remain unclear. Using female BALB/c mice with 60 mm³ tumors, we injected mice tail with 25 mg/kg body weight Icariside II or DMSO. After harvesting the tumor, immunohistochemistry and western blot were performed to detect MMP2/9 levels. Icariside II injection significantly inhibited MMP2/9 protein expression. The cell migration assays revealed that Icarisdie II inhibited the wound closure rate and the ability of Hela cell crossing the transwell chambers. Further, the key regulators in NF-κB and MAPK signaling pathway were detected in xenograft tumor and Hela cells by qPCR and western blot. JNK was screened out from several important signaling molecules, which had the same expression trend with MMP2/9. Finally, both 5 μM and 30 μM Icariside II weakened JNK-MMP2/9 signaling, despite the JNK activator Polyphyllin I and Anisomycin reversed the deficiencies. In this study, we proved that Icariside II can inhibit cervical cancer cells migration through JNK-MMP2/9 signaling pathway and is a prospective drug with high-chemopreventive effects on cervical cancer cell metastasis.

HAND2-AS1 inhibits invasion and metastasis of cervical cancer cells via microRNA-330-5p-mediated LDOC1

Background

Cervical cancer is a serious disease with complicated pathogenesis and thus there is an urgent need to find novel targets for the treatment. Recently, long non-coding RNAs (lncRNAs) have emerged as critical factors in tumorigenesis. In this study, we aimed to investigate the mechanism of HAND2 antisense RNA 1 (HAND2-AS1) on the invasion and metastasis of cervical cancer cells.

Methods

The expression patterns of HAND2-AS1, microRNA-330-5p (miR-330-5p) and leucine zipper down-regulated in cancer 1 (LDOC1) in cervical cancer were characterized by RT-qPCR and western blot analysis. Dual luciferase reporter assay and RIP were applied to verify relationship between HAND2-AS1, miR-330-5p and LDOC1. Fluorescence in situ hybridization (FISH) was used to detect the subcellular localization of HAND2-AS1. Besides, viability, invasion and migration ability of HeLa cells were investigated by cell counting kit-8 (CCK-8) and Transwell assays respectively. Hematoxylin-eosin staining was performed for lymph node metastasis detection. In addition, the tumor growth in nude mice was evaluated.

Results

Low expression of HAND2-AS1 and LDOC1, and high expression of miR-330-5p were detected in cervical cancer tissues and cells. It was found that binding of HAND2-AS1 to miR-330-5p results in upregulation of LDOC1 expression. Also, overexpressed HAND2-AS1 and LDOC1 or down-regulated miR-330-5p inhibited expression of proliferation-associated proteins Ki-67, PCNA, migration-associated proteins N-cad and invasion-related proteins MMP-2, MMP-9 as well as lymph node metastasis. Moreover, HAND2-AS1 inhibited tumor formation and lymph node metastasis by binding to miR-330-5p in vivo.

Conclusion

HAND2-AS1 promotes LDOC1 expression by competitively binding to miR-330-5p and consequently inhibiting cervical cancer cell invasion and metastasis. This could facilitate development of therapeutic strategies against cervical cancer.

Tumor suppressor LHPP regulates the proliferation of colorectal cancer cells via the PI3K/AKT pathway

Colorectal cancer (CRC) is the third most commonly diagnosed cancer and the fourth leading cause of cancer-related mortality worldwide. Thus, identification of the mechanisms involved in the progression of CRC has become a crucial element of facilitating early CRC diagnosis and targeted therapy for patients with advanced CRC. Currently, Phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP), a type of histidine phosphatase protein, has been confirmed as a tumor suppressor in hepatocellular carcinoma (HCC) and cervical cancer. However, the functions and molecular mechanisms underlying LHPP in CRC remain undefined. The present study revealed that dysregulation of LHPP was frequently observed in CRC tissues and was positively correlated with tumor severity and poor prognosis. Functional experiments demonstrated that overexpression of LHPP impeded CRC cell growth and proliferation in vitro, and was associated with a change in p53 expression and PI3K/AKT activity. In contrast, silencing of LHPP significantly promoted cell growth and proliferation by modulating the PI3K/AKT signaling pathway. Notably, the anti-CRC effects of LHPP were also observed in nude mouse in vivo experiments. Overall, the data obtained in the present study suggested that LHPP may be exploited as a diagnostic and prognostic candidate for patients with CRC.