G Protein-Coupled Receptor 87 (GPR87) Promotes Cell Proliferation in Human Bladder Cancer Cells

The path of GPR87: from a P2Y-like receptor to its role in cancer progression

GPR87 is a G protein-coupled seven-transmembrane receptor first described as an orphan receptor in 2001. Despite its high structural homology to several extracellular nucleotide-activated P2Y receptors and sharing conserved sequence motifs in transmembrane regions, identification of endogenous ligands from the class of nucleotides and their analogues has failed for GPR87. Although lysophosphatidic acid was proposed to be a natural ligand for this cell surface receptor, these data are preliminary and inconsistent, and IUPHAR is currently considering GPR87 as an orphan receptor. Thus, the endogenous ligands and physiological functions of GPR87 are still required to be determined and/or confirmed. The remarkably higher expression of GPR87 in human malignant tissues compared to the normal healthy ones clearly suggests that this receptor may be involved in the development and progression of cancerous neoplasms. Therefore, in this review article, the main focus is placed on the oncogenic role of GPR87 in various human malignancies, presenting it as a potential novel target site for therapeutic interventions using both humanized monoclonal antibodies and gene therapy but also selective antagonists which are still waiting for their identification. Furthermore, the importance of the expression of GPR87 as a predictive biomarker for evaluating the prognosis and overall survival of cancer patients is also highlighted.

SIGMAR1 screened by a GPCR-related classifier regulates endoplasmic reticulum stress in bladder cancer

BACKGROUND

Bladder cancer (BC) is one of the most common malignancies worldwide. G protein-coupled receptors (GPCRs) are a large family of transmembrane proteins that are increasingly recognised as key players in cancer biology, affecting cell signalling and the tumour microenvironment. The sigma-1 receptor (SIGMAR1), although not a classical GPCR, has similar functions and is associated with the regulation of ER stress. However, its specific role and mechanism in bladder cancer are still unclear.

METHOD

The data sets pertaining to batch sequencing, single-cell RNA sequencing (scRNA-seq), immunotherapy response and clinical pathological characteristics were obtained from the public database. Thereafter, multiple algorithms were employed for the screening of GPCRs and immune cells related to the prognosis of BC. A GPCR-tumour microenvironment (TME) classifier was constructed and validated using different queues and multi-omics methods. The key biological pathways between GPCR-TME subgroups were identified through the utilisation of methodologies such as Gene Set Enrichment Analysis (GSEA), Weighted Gene Co-expression Network Analysis (WGCNA), and Tumour Immunophenotype Tracking (TIP). The expression of SIGMAR1 in BC cell lines and tissue samples was validated by western blotting. The Gene Ontology (GO) and GSEA were employed for biological process enrichment analysis. The biological role of SIGMAR1 in BC was investigated through functional experiments and subcutaneous tumour-bearing experiments in nude mice. The relationship between SIGMAR1 and immune cell infiltration was explored using the CIBERSORT method.

RESULTS

A total of 15 types of GPCR and 5 types of immune cells were identified and established as a GPCR-TME classifier. Patients in the GPCR-low + TME-high group exhibited the most favourable prognosis, whereas patients in the GPCR-high + TME-low group demonstrated the least favourable prognosis. The scRNA-seq results revealed an increase in GPCR expression in CD8 + T cells, endothelial cells, and NK cells. GPCR-TME was significantly correlated with overall survival (OS) in BC patients and outperformed a range of clinical parameters, making it an independent risk factor affecting the prognosis of BC patients. In comparison to normal tissues, SIGMAR1 was markedly expressed in BC tissues, and was associated with a poor prognosis. Functional experiments demonstrated that SIGMAR1 deficiency impeded the invasive capacity of cancer cells and restrained cellular proliferation. Moreover, in vivo experiments corroborated that SIGMAR1 deficiency curtailed the growth of xenografts in nude mice. Western blotting analysis revealed that SIGMAR1 silencing intensified endoplasmic reticulum (ER) stress in BC cells and promoted cell apoptosis. Additionally, the expression level of SIGMAR1 was correlated with the level of immune cell infiltration and immune-related functions.

CONCLUSION

The construction of a BC-related GPCR-TME classifier enabled the effective prediction of the OS of BC patients and the identification of SIGMAR1, a key factor regulating ER stress in BC. The knockout of SIGMAR1 can destroy its protective effect on ER stress, enhance apoptosis of BC cells, and facilitate further investigation of novel treatment strategies for cancer therapy.

An update on regulation and function of G protein-coupled receptors in cancer: A promising strategy for cancer therapy

G protein-coupled receptors (GPCRs) are a large family of cell surface receptors that play a crucial role in signal transduction and cellular communication. GPCR proteins are involved in a wide range of physiological processes, including cell growth, migration, and survival. Dysregulation of GPCR protein expression has been implicated in the pathogenesis of various diseases, including cancer, and GPCR proteins have been shown to modulate these processes in various types of cancer, highlighting their importance as potential therapeutic targets. In this review, we summarize the expression regulation of GPCRs in cancer cells, update the various ways by which the abnormal expression of GPCR protein affects the behavior of tumor cells, and discuss the current research directions and potentially facing problems of strategies on GPCR-targeting therapy.

GPR87 promotes renal tubulointerstitial fibrosis by accelerating glycolysis and mitochondrial injury

Renal tubulointerstitial fibrosis is the hallmark of chronic kidney disease (CKD) and the best predictor of renal survival. However, current treatments for CKD remain extremely limited. Therefore, novel therapeutic targets are urgently needed to either stop or reverse CKD progression. The present study was designed to explore the potential role of GPR87, a member of the G protein-coupled receptors (GPCRs) family, in the pathogenesis of tubulointerstitial fibrosis. It was found that GPR87 was significantly induced in the kidney, especially in tubular areas, from different mouse models of renal fibrosis, including unilateral ureteral obstruction (UUO) nephropathy, aristolochic acid nephropathy, and diabetic nephropathy, respectively. Tubule-specific GPR87 deletion dramatically ameliorated tubulointerstitial fibrosis in UUO mice. Mechanistically, GPR87 accelerated glycolysis and mitochondrial injury by YAP-hexokinase-2 signaling, thereby promoting renal fibrosis. Importantly, the upregulation of GPR87 was also found in the kidney from patients with various CKD, indicating that the induction of GPR87 may be a common feature of human kidney diseases. Collectively, our studies for the first time demonstrate that GPR87 plays a pivotal role in renal fibrosis at least in part by accelerating glycolysis and mitochondrial injury, suggesting that targeting GPR87 may represent a novel therapeutic strategy for patients with CKD.

Genomic Analyses for Selective Signatures and Genes Involved in Hot Adaptation Among Indigenous Chickens From Different Tropical Climate Regions

Climate change, especially weather extremes like extreme cold or extreme hot, is a major challenge for global livestock. One of the animal breeding goals for sustainable livestock production should be to breed animals with excellent climate adaptability. Indigenous livestock and poultry are well adapted to the local climate, and they are good resources to study the genetic footprints and mechanism of the resilience to weather extremes. In order to identify selection signatures and genes that might be involved in hot adaptation in indigenous chickens from different tropical climates, we conducted a genomic analysis of 65 indigenous chickens that inhabit different climates. Several important unique positively selected genes (PSGs) were identified for each local chicken group by the cross-population extended haplotype homozygosity (XP-EHH). These PSGs, verified by composite likelihood ratio, genetic differentiation index, nucleotide diversity, Tajima’s D, and decorrelated composite of multiple signals, are related to nerve regulation, vascular function, immune function, lipid metabolism, kidney development, and function, which are involved in thermoregulation and hot adaptation. However, one common PSG was detected for all three tropical groups of chickens via XP-EHH but was not confirmed by other five types of selective sweep analyses. These results suggest that the hot adaptability of indigenous chickens from different tropical climate regions has evolved in parallel by taking different pathways with different sets of genes. The results from our study have provided reasonable explanations and insights for the rapid adaptation of chickens to diverse tropical climates and provide practical values for poultry breeding.

Single-cell RNA sequencing identifies G-protein coupled receptor 87 as a basal cell marker expressed in distal honeycomb cysts in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a devastating and life-threatening lung disease characterised by epithelial reprogramming and increased extracellular matrix deposition leading to loss of lung function. Prominent histopathological structures in the distal IPF lung include honeycomb cysts in the alveolar space [1]. These are heterogeneous bronchiolised areas that feature clusters of simple epithelium with keratin (KRT)5+ basal-like cells interspersed with pseudostratified epithelium containing differentiated, hyperplastic epithelial cells, as well as aberrant ciliated cells [2–5]. Recent single-cell RNA sequencing studies of whole lungs from IPF and donor tissue revealed cellular subtypes unique to IPF, including basaloid KRT5−/KRT17+ cells present in the distal lung [6–10].

Bronchiolisation and honeycombing are features of IPF. ScRNA sequencing identified GPR87 as a novel marker of basal cells in IPF, enriched in honeycomb cysts. GPR87 overexpression resulted in aberrant airway cell differentiation. https://bit.ly/3i4dXeT

GPR87 Promotes Metastasis through the AKT-eNOS-NO Axis in Lung Adenocarcinoma

Lung adenocarcinoma is one of the leading causes of cancer-related deaths. Despite the availability of advanced anticancer drugs for lung cancer treatment, the prognosis of patients still remains poor. There is a need to explore novel oncogenic mechanisms to overcome these therapeutic limitations. The functional experiments in vitro and in vivo were performed to evaluate the role of GPR87 expression on lung adenocarcinoma metastasis. The public lung adenocarcinoma dataset was used to determine the clinical relevance of GPR87 expression in patients with lung adenocarcinoma. GPR87 is upregulated in various cancer; however, the biological function of GPR87 has not yet been established in lung adenocarcinoma. In this study, we found that GPR87 expression is upregulated in lung adenocarcinoma and is associated with poor patient prognosis. Additionally, we showed that GPR87 overexpression promotes invasiveness and metastasis of lung adenocarcinoma cells. Furthermore, we demonstrated that AKT-eNOS-NO signaling is a novel downstream pathway of GPR87 in lung adenocarcinoma. Conversely, we confirmed that silencing of GPR87 expression suppressed these phenotypes. Our results reveal the oncogenic function of GPR87 in cancer progression and metastasis through the activation of eNOS as a key mediator. Therefore, we propose that targeting eNOS could be a novel therapeutic strategy to improve the clinical treatment of lung adenocarcinoma.

Development and Validation of a Combined Glycolysis and Immune Prognostic Model for Melanoma

Background

Glycolytic effects and immune microenvironments play important roles in the development of melanoma. However, reliable biomarkers for prognostic prediction of melanoma as based on glycolysis and immune status remain to be identified.

Methods

Glycolysis-related genes (GRGs) were obtained from the Molecular Signatures database and immune-related genes (IRGs) were downloaded from the ImmPort dataset. Prognostic GRGs and IRGs in the TCGA (The Cancer Genome Atlas) and GSE65904 datasets were identified. Least absolute shrinkage and selection operator (LASSO) Cox regression and multivariate Cox regression were used for model construction. Glycolysis expression profiles and the infiltration of immune cells were analyzed and compared. Finally, in vitro experiments were performed to assess the expression and function of these CIGI genes.

Results

Four prognostic glycolysis- and immune-related signatures (SEMA4D, IFITM1, KIF20A and GPR87) were identified for use in constructing a comprehensive glycolysis and immune (CIGI) model. CIGI proved to be a stable, predictive method as determined from different datasets and subgroups of patients and served as an independent prognostic factor for melanoma patients. In addition, patients in the high-CIGI group showed increased levels of glycolytic gene expressions and exhibited immune-suppressive features. Finally, SEMA4D and IFITM1 may function as tumor suppressor genes, while KIF20A and GPR87 may function as oncogenes in melanoma as revealed from results of in vitro experiments.

Conclusion

In this report we present our findings on the development and validation of a novel prognostic classifier for use in patients with melanoma as based on glycolysis and immune expression profiles.

Development of multi-epitope vaccine constructs for non-small cell lung cancer (NSCLC) against USA human leukocyte antigen background: an immunoinformatic approach toward future vaccine designing

OBJECTIVES

The design of peptide-based vaccines for cancer is a promising immunotherapy that can induce a cancer-specific cytotoxic response in tumor cells.

METHODS

Herein, we used the immunoinformatic approach in designing a multi-epitope vaccine targeting G-protein coupled receptor 87 (GPCR-87), cystine/glutamate transporter (SLC7A11), Immunoglobulin binding protein 1 (IGBP1), and thioredoxin domain-containing protein 5 (TXNDC5), which can potentially contribute to NSCLC. The MHC-I and MHC-II epitopes selected for the fusion construct were evaluated for their antigenic and non-allergenic natures via VaxiJen and AllerTop.

RESULTS

A total of five epitopes, four class-I (FIFYLKNIV, CRYTSVLFY, RYLKVVKPF, and RQAKIQRYK), and one class-II (NQVRGYPTLLWFRDG), having combined USA population coverage of 100%, were used to make ten possible multi-epitope fusion constructs. In these constructs, PADRE, a universal T-helper epitope, and RSO9, a TLR4 agonist, were fused as adjuvants. The molecular docking analysis revealed that two constructs were showing significant binding affinities toward HLA-A*02:01, the most prevalent HLA allele in USA. Moreover, MD simulations marked one construct as a promising therapeutic candidate.

CONCLUSION

The multi-epitope vaccine constructs designed using immunogenic, and non-allergenic peptides of NSCLS tumor-associated proteins are likely to pose significant therapeutic efficacies in cancer immunotherapy due to their high binding affinities toward HLA molecules.

A Novel Risk Factor Model Based on Glycolysis-Associated Genes for Predicting the Prognosis of Patients With Prostate Cancer

BACKGROUND

Prostate cancer (PCa) is one of the most prevalent cancers among males, and its mortality rate is increasing due to biochemical recurrence (BCR). Glycolysis has been proven to play an important regulatory role in tumorigenesis. Although several key regulators or predictors involved in PCa progression have been found, the relationship between glycolysis and PCa is unclear; we aimed to develop a novel glycolysis-associated multifactor prediction model for better predicting the prognosis of PCa.

METHODS

Differential mRNA expression profiles derived from the Cancer Genome Atlas (TCGA) PCa cohort were generated through the "edgeR" package. Glycolysis-related genes were obtained from the GSEA database. Univariate Cox and LASSO regression analyses were used to identify genes significantly associated with disease-free survival. ROC curves were applied to evaluate the predictive value of the model. An external dataset derived from Gene Expression Omnibus (GEO) was used to verify the predictive ability. Glucose consumption and lactic production assays were used to assess changes in metabolic capacity, and Transwell assays were used to assess the invasion and migration of PC3 cells.

RESULTS

Five glycolysis-related genes were applied to construct a risk score prediction model. Patients with PCa derived from TCGA and GEO (GSE70770) were divided into high-risk and low-risk groups according to the median. In the TCGA cohort, the high-risk group had a poorer prognosis than the low-risk group, and the results were further verified in the GSE70770 cohort. In vitro experiments demonstrated that knocking down HMMR, KIF20A, PGM2L1, and ANKZF1 separately led to less glucose consumption, less lactic production, and inhibition of cell migration and invasion, and the results were the opposite with GPR87 knockdown.

CONCLUSION

The risk score based on five glycolysis-related genes may serve as an accurate prognostic marker for PCa patients with BCR.

Knockdown of RRM1 with Adenoviral shRNA Vectors to Inhibit Tumor Cell Viability and Increase Chemotherapeutic Sensitivity to Gemcitabine in Bladder Cancer Cells

RRM1-an important DNA replication/repair enzyme-is the primary molecular gemcitabine (GEM) target. High RRM1-expression associates with gemcitabine-resistance in various cancers and RRM1 inhibition may provide novel cancer treatment approaches. Our study elucidates how RRM1 inhibition affects cancer cell proliferation and influences gemcitabine-resistant bladder cancer cells. Of nine bladder cancer cell lines investigated, two RRM1 highly expressed cells, 253J and RT112, were selected for further experimentation. An RRM1-targeting shRNA was cloned into adenoviral vector, Ad-shRRM1. Gene and protein expression were investigated using real-time PCR and western blotting. Cell proliferation rate and chemotherapeutic sensitivity to GEM were assessed by MTT assay. A human tumor xenograft model was prepared by implanting RRM1 highly expressed tumors, derived from RT112 cells, in nude mice. Infection with Ad-shRRM1 effectively downregulated RRM1 expression, significantly inhibiting cell growth in both RRM1 highly expressed tumor cells. In vivo, Ad-shRRM1 treatment had pronounced antitumor effects against RRM1 highly expressed tumor xenografts (p < 0.05). Moreover, combination of Ad-shRRM1 and GEM inhibited cell proliferation in both cell lines significantly more than either treatment individually. Cancer gene therapy using anti-RRM1 shRNA has pronounced antitumor effects against RRM1 highly expressed tumors, and RRM1 inhibition specifically increases bladder cancer cell GEM-sensitivity. Ad-shRRM1/GEM combination therapy may offer new treatment options for patients with GEM-resistant bladder tumors.

Inhibition of transforming growth factor-beta by Tranilast reduces tumor growth and ameliorates fibrosis in colorectal cancer

Transforming Growth Factor-beta (TGF-β) is dysregulated in colorectal cancer and there is growing evidence that it is associated with a poor prognosis and chemo-resistance in several malignances, including CRC. In this study we have explored the therapeutic potential of targeting TGF-β using Tranilast in colon cancer. The anti-proliferative activity of Tranilast was evaluated in 2- and 3-dimensional cells. We used a xenograft model of colon cancer to investigate the activity of Tranilast alone or in combination with 5-FU on tumor growth using histological staining and biochemical studies, as well as gene expression analyses using RT-PCR and Western blotting. Tranilast alone or in combination with 5-FU inhibited tumor growth and was associated with a reduction of TGF-β expression and CD31 positive endothelial cells. Histological evaluation showed that Tranilast increased tumor necrosis and reduced tumor density and angiogenesis. Tranilast increased MDA and ROS production. It was also found that Tranilast reduced total thiol concentration and reduced SOD and catalase activity. Tranilast plus 5-FU was also found to attenuate collagen deposition, reducing tumor fibrosis in tumor xenografts. Our results show that Tranilast, a TGF inhibitor, in combination with 5-FU reduces tumor growth by inhibiting fibrosis and inducting ROS, thus supporting this therapeutic approach in CRC treatment.

Taurine attenuates gossypol-induced apoptosis of C2C12 mouse myoblasts via the GPR87-AMPK/AKT signaling

Gossypol, a toxic polyphenol extracted from cotton seeds, is hazardous to human and animal health. Taurine is considered as an essential or semi-essential amino acid and has diverse cytoprotective effects. This study was aimed to investigate the protective effect and molecular mechanism of taurine against apoptosis of C2C12 mouse myoblasts induced by gossypol. C2C12 mouse myoblasts were exposed to gossypol (0, 1 nM, 10 nM, 100 nM, 1 μM, and 10 μM). Cell numbers were rapidly decreased with increasing concentrations of gossypol. Gossypol significantly induced apoptosis, decreased Bcl2 expression, and increased the protein levels of Bax and the cleaved caspase 3. Taurine (0.24 mM) treatment largely rescued the cell number decreased by gossypol, attenuated gossypol-induced cell apoptosis. GPR87 knockdown abolished the inhibition by taurine of cell apoptosis. Furthermore, GPR87 overexpression attenuated cell apoptosis induced by gossypol. Both taurine treatment and GPR87 overexpression stimulated AKT phosphorylation but inhibited AMPK phosphorylation, whereas gossypol had the opposite effects. Taurine treatment promoted GPR87 expression and subcellular localization and partially rescued the inhibition of gossypol on this expression. In summary, these data reveal that taurine attenuates gossypol-induced apoptosis of C2C12 mouse myoblasts via the GPR87-AMPK/AKT signaling.

Pancreatic Adenocarcinoma: Unconventional Approaches for an Unconventional Disease

This review highlights current treatments, limitations, and pitfalls in the management of pancreatic cancer and discusses current research in novel targets and drug development to overcome these clinical challenges. We begin with a review of the clinical landscape of pancreatic cancer, including genetic and environmental risk factors, as well as limitations in disease diagnosis and prevention. We next discuss current treatment paradigms for pancreatic cancer and the shortcomings of targeted therapy in this disease. Targeting major driver mutations in pancreatic cancer, such as dysregulation in the KRAS and TGFβ signaling pathways, have failed to improve survival outcomes compared with nontargeted chemotherapy; thus, we describe new advances in therapy such as Ras-binding pocket inhibitors. We then review next-generation approaches in nanomedicine and drug delivery, focusing on preclinical advancements in novel optical probes, antibodies, small-molecule agents, and nucleic acids to improve surgical outcomes in resectable disease, augment current therapies, expand druggable targets, and minimize morbidity. We conclude by summarizing progress in current research, identifying areas for future exploration in drug development and nanotechnology, and discussing future prospects for management of this disease.

RNA Sequencing Revealed Signals of Evolution From Gallbladder Stone to Gallbladder Carcinoma

Gallbladder stone is a major risk factor for gallbladder carcinoma (GBC), while there is still a controversy whether period of follow-up since newly diagnoses of asymptomatic gallstones increases the risk of GBC. In this study, 10 GBC patients and 30 patients with gallstones were admitted to our hospital. Patients with gallstones were divided into 3 groups according to the follow-up time, involving 10 patients with follow-up period of 1–3 years (GS3 group), 10 patients with follow-up period of 5–10 years (GS5 group), and 10 patients with follow-up period of more than 10 years (GS10 group). Tumor and para-tumor tissues of GBC patients, and gallbladder tissues of gallstone patients were collected. RNA sequencing was performed on the 50 samples. Besides, 1,704 differentially expressed genes (DEGs) were identified in tumors compared with para-tumor tissues of 10 GBC patients, which were enriched into some well-known cancer-related pathways, such as PI3K-Akt, mitogen-activated protein kinase (MAPK), Ras, and Wnt signaling pathways, and the most significant pathway was neuroactive ligand-receptor interaction. Patients with gallstones with periods of follow-up equal to 1–3 and > 10 years showed to have higher cancer risk than those with 5–10 years. ALPP and GPR87 are potential biomarkers for predicting cancer risk in patients with gallstones. The in vitro results revealed that GPR-87 can promote the proliferation, migration, and invasion of GBC cells. Herein, we explored the relationship between GBC patients and patients with gallstones with different periods of follow-up in transcriptome level.

G Protein-Coupled Receptor GPR87 Promotes the Expansion of PDA Stem Cells through Activating JAK2/STAT3

Cancer stem cells are the main reason for drug resistance and tumor relapse, and screening the targets for cancer stem cells is essential for tumor therapy. Here, we studied the role and regulatory mechanism of a G protein-coupled receptor named as G protein-coupled receptor 87 (GPR87) in the expansion of pancreatic ductal adenocarcinoma (PDA) stem cells. We found that GPR87 was an independent prognostic factor for PDA patients: patients with high GPR87 had a poor outcome. GPR87 significantly promoted the sphere formation ability, increased side population (SP) cell number, increased the expression of PDA stem cell markers, and increased the tumor initiation ability, suggesting that GPR87 promotes the expansion of PDA stem cells. Mechanism analysis suggested that signal transducer and activator of transcription 3 (STAT3) directly bound to the promoter of GPR87 to increase GPR87 expression; inversely, GPR87 also activated STAT3. Further analysis suggested that GPR87 activated Janus kinase 2 (JAK2), which can activate STAT3, inhibiting JAK2 activation in GPR87-overexpressing PDA cells, which significantly inhibited the expansion of PDA stem cells; these findings suggested that GPR87, JAK2, and STAT3 formed a positive feedback loop increasing PDA stem cell population. In PDA specimens, GPR87 expression is positively correlated with the phosphorylation level of STAT3 and JAK2, confirming GPR87 promoted PDA stem cell expansion through activating JAK2/STAT3. In summary, we found that GPR87, together with JAK2 and STAT3, formed a positive feedback loop to promote the expansion of PDA stem cells.

CD90 determined two subpopulations of glioma-associated mesenchymal stem cells with different roles in tumour progression

Human glioma-associated mesenchymal stem cells (gbMSCs) are the stromal cell components that contribute to the tumourigenesis of malignant gliomas. Recent studies have shown that gbMSCs consist of two distinct subpopulations (CD90⁺ and CD90⁻ gbMSCs). However, the different roles in glioma progression have not been expounded. In this study, we found that the different roles of gbMSCs in glioma progression were associated with CD90 expression. CD90^high gbMSCs significantly drove glioma progression mainly by increasing proliferation, migration and adhesion, where as CD90^low gbMSCs contributed to glioma progression chiefly through the transition to pericytes and stimulation of vascular formation via vascular endothelial cells. Furthermore, discrepancies in long non-coding RNAs and mRNAs expression were verified in these two gbMSC subpopulations, and the potential underlying molecular mechanism was discussed. Our data confirm for the first time that CD90^high and CD90^low gbMSCs play different roles in human glioma progression. These results provide new insights into the possible future use of strategies targeting gbMSC subpopulations in glioma patients.

High expression of GPR116 indicates poor survival outcome and promotes tumor progression in colorectal carcinoma

Previous studies have found that G-protein-coupled receptor 116 (GPR116) is a regulator of breast cancer metastasis. However, the role of GPR116 in colorectal carcinoma (CRC) carcinogenesis and progression is unknown. In this study, We found GPR116 expression was significantly up-regulated in CRC specimens compared with corresponding non-cancerous tissues. Increased GPR116 expression in CRC was correlated with histological differentiation and distant metastasis. In addition, high expression of GPR116 was significantly associated with poor overall survival of CRC patients, which was also confirmed by GSE14333, GSE17536 and GSE33113 datasets from the Gene Expression Omnibus (GEO). Furthermore, we demonstrated that the ability of proliferation and invasion of CRC cell lines HCT116 and LOVO was markedly reduced after transfected with siRNA-GPR116. Meanwhile, GPR116 may drive EMT in CRC cells through AKT/EKR signaling pathway, resulting in metastasis. Thus, GPR116 may be a novel reliable prognostic indicator and a risk factor in CRC progression.

Glaucocalyxin A induces G2/M cell cycle arrest and apoptosis through the PI3K/Akt pathway in human bladder cancer cells

Glaucocalyxin A (GLA), a major component isolated from Rabdosia japonica, has been proven to show anti-bacterial and anti-tumor biological characteristics according to previous studies. However, its potential effect on bladder cancer remains unknown. The present research aims to investigate the underlying mechanism in treating bladder cancer in vivo and in vitro. Cell proliferation was analyzed by CCK-8 assay and colony formation. Flow cytometry was used to measure the cell cycle distribution and apoptosis. The expressions of the cell cycle and apoptosis-related proteins were detected by western blotting and immunofluorescence staining. Meanwhile, the in vivo study was performed to evaluate the anti-tumor effect on a UMUC3 subcutaneous tumor of NOD/SCID mice model. GLA suppressed colony-formation ability, triggered G2/M arrest and promoted apoptosis of UMUC3 cells in a dose-dependent manner. Furthermore, western blotting showed that GLA downregulated the expressions of PI3K p85, p-Akt, Bcl-2, CDK1, Cyclin B1 whereas upregulated the levels of PTEN, Bax, Cleaved Caspase-3. In vivo, GLA at a dosage of 20 mg/kg significantly inhibited tumor growth compared with the control group by intraperitoneal injection. These results suggested that GLA-related G2/M arrest and apoptosis in UMUC3 cells were mediated by a suppressed PI3K/Akt signaling pathway, which regulated p21^Waf1/Cip1 as well as intrinsic caspase cascade. Collectively, our observations could help to develop new drugs targeting the PI3K/Akt pathway for the treatment of bladder cancer.

Proteomics analysis of altered proteins in kidney of mice with aristolochic acid nephropathy using the fluorogenic derivatization-liquid chromatography-tandem mass spectrometry method

Aristolochic acid (AA) causes interstitial renal fibrosis, called aristolochic acid nephropathy (AAN). There is no specific indicator for diagnosing AAN, so this study aimed to investigate the biomarkers for AAN using a proteomics method. The C3H/He female mice were given ad libitum AA-distilled water (0.5 mg/kg/day) and distilled water for 56 days in the AA and normal groups, respectively. The AA-induced proteins in the kidney were investigated using a proteomics study, including fluorogenic derivatization with 7-chloro-N-[2-(dimethylamino)ethyl]-2,1,3-benzoxadiazole-4-sulfonamide, followed by high-performance liquid chromatography analysis and liquid chromatography tandem mass spectrometry with a MASCOT database searching system. There were two altered proteins, thrombospondin type 1 (TSP1) and G protein-coupled receptor 87 (GPR87), in the kidney of AA-group mice on day 56. GPR87, a tumorigenesis-related protein, is reported for the first time in the current study. The renal interstitial fibrosis was certainly induced in the AA-group mice under histological examination. Based on the results of histological examination and the proteomics study, this model might be applied to AAN studies in the future. TSP1 might be a novel biomarker for AAN, and the further role of GPR87 leading to AA-induced tumorigenesis should be researched in future studies.

Transcriptome-wide elucidation of liposomal formulations for anticancer drug delivery

Although widely used in chemotherapy, free doxorubicin (Dox) might enhance cell malignancy undesirably. Liposomal Dox (Doxlipo) has been clinically approved for the treatment of breast cancer due to reduced systematical toxicity and increased tumor targeting, yet the transcriptome-wide elucidation of the Doxlipo formulations remains elusive. To this end, we explored the impact of two Dox liposomal formulations, Doxlipo mainly containing hydrogenated soy phosphatidylcholine or 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, on the transcriptional pattern of MCF-7 cells. The two types of Dox liposomal formulations with different drug release kinetics were investigated to reveal the relationship between the formulation and tumor malignancy. Interestingly, we found that liposomal formulation significantly altered the transcriptional pattern of a wide range of genes. Under equivalent dosage of Dox, free Dox substantially changed the expression of ANK1, ACTA2, GPR87, GDF15, FZD6, and WNT4 in MCF-7 cells. Notably, free Dox induced much higher expression of ABCB1 and significantly enhanced the cell migration behavior in comparison with HSPC Doxlipo under a similar level of cytotoxicity. Finally, siRNA targeting GPR87 was codelivered with cationic Doxlipo to reduce the expression of malignancy-related genes. Our study, for the first time, provides an overview of the influence of formulation on the malignancy at transcriptional level and reveals the relationship between cytotoxicity and cell malignancy from the formulation aspect, offering valuable reference for the future formulation design for anticancer drug delivery.

Overexpression of G protein-coupled receptor GPR87 promotes pancreatic cancer aggressiveness and activates NF-κB signaling pathway

Background

Pancreatic cancer is a highly lethal disease and has the worst prognosis of any major malignancy. G protein-coupled receptor GPR87 is reported to be overexpressed in multiple cancers. The clinical significance and biological role of GPR87 in pancreatic cancer, however, remain to be established.

Methods

GPR87 expression in pancreatic cancer cell lines, paired patient tissues were determined using western blotting and Real-time PCR. Ninety-six human pancreatic cancer tissue samples were analyzed by immunochemistry (IHC) to investigate the association between GPR87 expression and the clinicopathological characteristics of pancreatic cancer. Functional assays, such as anchorage-independent growth, chicken chorioallantoic membrane (CAM) assay, transwell matrix penetration assay, and Annexin V-FITC and PI staining and a xenograft tumor model were used to determine the oncogenic role of GPR87 in human pancreatic cancer progression. The effect of GPR87 on NF-κB signaling pathway was further investigated using the luciferase reporter assays, and by detection of the NF-κB signaling downstream genes.

Results

Herein, we reported that GPR87 was markedly overexpressed in pancreatic cancer cells and clinical tissues. Immunohistochemical analysis showed that the expression of GPR87 significantly correlated with patients’ clinicopathologic features, including clinical stage and tumor-nodule-metastasis (TNM) classification. Pancreatic cancer patients with higher levels of GPR87 expression had shorter overall survival compared to patients with lower GPR87 levels. We gained valuable insights into the mechanism of GPR87 expression in pancreatic cancer cells by demonstrating that overexpressing GPR87 significantly enhanced, whereas silencing endogenous GPR87 inhibited, the proliferation, angiogenesis and increased resistance to gemcitabine-induced apoptosis of pancreatic cancer in vitro and tumorigenicity of pancreatic cancer cells in vivo. Finally, we demonstrated that GPR87 enhanced pancreatic cancer aggressiveness by activating NF-κB signaling pathway. Conclusions: Taken together, these findings suggest that GPR87 plays a critical oncogenic role in pancreatic cancer progression and highlight its potential as a target for pancreatic cancer therapy.

Conclusions

Our findings suggest that GPR87 plays a critical oncogenic role in pancreatic cancer progression and highlight its potential as a target for pancreatic cancer therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-017-0627-6) contains supplementary material, which is available to authorized users.

Signaling via G proteins mediates tumorigenic effects of GPR87

G protein-coupled receptors (GPCRs) constitute a large protein family of seven transmembrane (7TM) spanning proteins that regulate multiple physiological functions. GPR87 is overexpressed in several cancers and plays a role in tumor cell survival. Here, the basal activity of GPR87 was investigated in transiently transfected HEK293 cells, revealing ligand-independent coupling to Gα_i, Gα_q and Gα_12/13. Furthermore, GPR87 showed a ligand-independent G protein-dependent activation of the downstream transcription factors CREB, NFκB, NFAT and SRE. In tetracycline-induced Flp-In T-Rex-293 cells, GPR87 induced cell clustering presumably through Gα_12/13 coupling. In a foci formation assay using retrovirally transduced NIH3T3 cells, GPR87 showed a strong in vitro transforming potential, which correlated to the in vivo tumor induction in nude mice. Importantly, we demonstrate that the transforming potential of GPR87 was correlated to the receptor signaling, as the signaling-impaired mutant R139A (Arg in the conserved "DRY"-motif at the bottom of transmembrane helix 3 of GPR87 substituted to Ala) showed a lower in vitro cell transformation potential. Furthermore, R139A lost the ability to induce cell clustering. In summary, we show that GPR87 is active through several signaling pathways and that the signaling activity is linked to the receptor-induced cell transformation and clustering. The robust surface expression of GPR87 and general high druggability of GPCRs make GPR87 an attractive future anticancer target for drugs that - through inhibition of the receptor signaling - will inhibit its transforming properties.