(Pro)renin receptor is crucial for glioma development via the Wnt/β-catenin signaling pathway

Role of renin angiotensin system inhibitors and metformin in Glioblastoma Therapy: a review

Glioblastoma multiforme (GBM) is a highly aggressive and incurable disease accounting for about 10,000 deaths in the USA each year. Despite the current treatment approach which includes surgery with chemotherapy and radiation therapy, there remains a high prevalence of recurrence. Notable improvements have been observed in persons receiving concurrent antihypertensive drugs such as renin angiotensin inhibitors (RAS) or the antidiabetic drug metformin with standard therapy. Anti-tumoral effects of RAS inhibitors and metformin have been observed in in vitro and in vivo studies. Although clinical trials have shown mixed results, the potential for the use of RAS inhibitors and metformin as adjuvant GBM therapy remains promising. Nevertheless, evidence suggest that these drugs exert multimodal antitumor actions; by particularly targeting several cancer hallmarks. In this review, we highlight the results of clinical studies using multidrug cocktails containing RAS inhibitors and or metformin added to standard therapy for GBM. In addition, we highlight the possible molecular mechanisms by which these repurposed drugs with an excellent safety profile might elicit their anti-tumoral effects. RAS inhibition elicits anti-inflammatory, anti-angiogenic, and immune sensitivity effects in GBM. However, metformin promotes anti-migratory, anti-proliferative and pro-apoptotic effects mainly through the activation of AMP-activated protein kinase. Also, we discussed metformin's potential in targeting both GBM cells as well as GBM associated-stem cells. Finally, we summarize a few drug interactions that may cause an additive or antagonistic effect that may lead to adverse effects and influence treatment outcome.

Upregulation of the Renin-Angiotensin System Is Associated with Patient Survival and the Tumour Microenvironment in Glioblastoma

Glioblastoma is a highly aggressive disease with poor survival outcomes. An emerging body of literature links the role of the renin-angiotensin system (RAS), well-known for its function in the cardiovascular system, to the progression of cancers. We studied the expression of RAS-related genes (ATP6AP2, AGTR1, AGTR2, ACE, AGT, and REN) in The Cancer Genome Atlas (TCGA) glioblastoma cohort, their relationship to patient survival, and association with tumour microenvironment pathways. The expression of RAS genes was then examined in 12 patient-derived glioblastoma cell lines treated with chemoradiation. In cases of glioblastoma within the TCGA, ATP6AP2, AGTR1, ACE, and AGT had consistent expressions across samples, while AGTR2 and REN were lowly expressed. High expression of AGTR1 was independently associated with lower progression-free survival (PFS) (p = 0.01) and had a non-significant trend for overall survival (OS) after multivariate analysis (p = 0.095). The combined expression of RAS receptors (ATP6AP2, AGTR1, and AGTR2) was positively associated with gene pathways involved in hypoxia, microvasculature, stem cell plasticity, and the molecular characterisation of glioblastoma subtypes. In patient-derived glioblastoma cell lines, ATP6AP2 and AGTR1 were upregulated after chemoradiotherapy and correlated with an increase in HIF1A expression. This data suggests the RAS is correlated with changes in the tumour microenvironment and associated with glioblastoma survival outcomes.

Elucidating the Role of Pro-renin Receptors in Pancreatic Ductal Adenocarcinoma Progression: A Novel Therapeutic Target in Cancer Therapy

Pancreatic cancer is a highly aggressive malignancy with a very poor prognosis. The 5- year survival in these patients is very low, and most patients develop drug resistance to current therapies, so additional studies are needed to identify the potential role of new drug targets for the treatment of pancreatic cancer. Recent investigations have been performed regarding the roles of pro-renin receptors (PRR) in the initiation and development of cancers. PRR is a component of the local renin-angiotensin system (RAS). Local tissue RAS has been known in diverse organ systems, including the pancreas. Various investigations have implicated that PRRs are associated with the upregulation of various signaling pathways, like the renin-angiotensin system pathway, PI3K/Akt/mTOR, and the Wnt-signaling pathways, to contribute to pathological conditions, including cancer. In this review, we presented an overview of the role of PRR in the progression of pancreatic adenocarcinoma.

Antiproliferative effects of D-allose associated with reduced cell division frequency in glioblastoma

Recent studies have shown that D-allose, a rare sugar, elicits antitumor effects on different types of solid cancers, such as hepatocellular carcinoma, non-small-cell lung cancer, and squamous cell carcinoma of the head and neck. In this study, we examined the effects of D-allose on the proliferation of human glioblastoma (GBM) cell lines (i.e., U251MG and U87MG) in vitro and in vivo and the underlying mechanisms. D-allose treatment inhibited the proliferation of U251MG and U87MG cells in a dose-dependent manner (3-50 mM). However, D-allose treatment did not affect cell cycles or apoptosis in these cells but significantly decreased the cell division frequency in both GBM cell lines. In a subcutaneous U87MG cell xenograft model, intraperitoneal injection of D-allose (100 mg/kg/day) significantly reduced the tumor volume in 28 days. These data indicate that D-allose-induced reduction in cell proliferation is associated with a subsequent decrease in the number of cell divisions, independent of cell-cycle arrest and apoptosis. Thus, D-allose could be an attractive additive to therapeutic strategies for GBM.

The renin-angiotensin-aldosterone system (RAAS) signaling pathways and cancer: foes versus allies

The renin-angiotensin-aldosterone system (RAAS), is an old system with new fundamental roles in cancer biology which influences cell growth, migration, death, and metastasis. RAAS signaling enhances cell proliferation in malignancy directly and indirectly by affecting tumor cells and modulating angiogenesis. Cancer development may be influenced by the balance between the ACE/Ang II/AT1R and the ACE2/Ang 1-7/Mas receptor pathways. The interactions between Ang II/AT1R and Ang I/AT2R as well as Ang1-7/Mas and alamandine/MrgD receptors in the RAAS pathway can significantly impact the development of cancer. Ang I/AT2R, Ang1-7/Mas, and alamandine/MrgD interactions can have anticancer effects while Ang II/AT1R interactions can be involved in the development of cancer. Evidence suggests that inhibitors of the RAAS, which are conventionally used to treat cardiovascular diseases, may be beneficial in cancer therapies.Herein, we aim to provide a thorough description of the elements of RAAS and their molecular play in cancer. Alongside this, the role of RAAS components in sex-dependent cancers as well as GI cancers will be discussed with the hope of enlightening new venues for adjuvant cancer treatment.

Drug Repositioning for Refractory Benign Tumors of the Central Nervous System

Drug repositioning (DR) is the process of identifying novel therapeutic potentials for already-approved drugs and discovering new therapies for untreated diseases. DR can play an important role in optimizing the pre-clinical process of developing novel drugs by saving time and cost compared with the process of de novo drug discovery. Although the number of publications related to DR has rapidly increased, most therapeutic approaches were reported for malignant tumors. Surgical resection represents the definitive treatment for benign tumors of the central nervous system (BTCNS). However, treatment options remain limited for surgery-, chemotherapy- and radiation-refractory BTCNS, as well as malignant tumors. Meningioma, pituitary neuroendocrine tumor (PitNET), and schwannoma are the most common BTCNS. The treatment strategy using DR may be applied for refractory BTCNS, such as Grade 2 meningiomas, neurofibromatosis type 2-related schwannomatosis, and PitNETs with cavernous sinus invasion. In the setting of BTCNS, stable disease can provide significant benefit to the patient. DR may provide a longer duration of survival without disease progression for patients with refractory BTCNS. This article reviews the utility of DR for refractory BTCNS.

Multiple therapeutic approaches of glioblastoma multiforme: From terminal to therapy

Glioblastoma multiforme (GBM) is an aggressive brain cancer showing poor prognosis. Currently, treatment methods of GBM are limited with adverse outcomes and low survival rate. Thus, advancements in the treatment of GBM are of utmost importance, which can be achieved in recent decades. However, despite aggressive initial treatment, most patients develop recurrent diseases, and the overall survival rate of patients is impossible to achieve. Currently, researchers across the globe target signaling events along with tumor microenvironment (TME) through different drug molecules to inhibit the progression of GBM, but clinically they failed to demonstrate much success. Herein, we discuss the therapeutic targets and signaling cascades along with the role of the organoids model in GBM research. Moreover, we systematically review the traditional and emerging therapeutic strategies in GBM. In addition, we discuss the implications of nanotechnologies, AI, and combinatorial approach to enhance GBM therapeutics.

ATP6AP2 is robustly expressed in pancreatic β cells and neuroendocrine tumors, and plays a role in maintaining cellular viability

ATP6AP2, also known as (pro)renin receptor, has been shown to be expressed in several tissues including pancreatic β cells. Whereas ATP6AP2 plays an important role in regulating insulin secretion in mouse pancreatic β cells, the expression profiles and roles of ATP6AP2 in human pancreatic endocrine cells and neuroendocrine tumor cells remain unclear. Here in this study, we investigated the expression profiles of ATP6AP2 in pancreatic endocrine cells, and found that ATP6AP2 is robustly expressed in pancreatic insulinoma cells as well as in normal β cells. Although ATP6AP2 was also expressed in low-grade neuroendocrine tumors, it was not or faintly detected in intermediate- and high-grade neuroendocrine tumors. Knockdown experiments of the Atp6ap2 gene in rat insulinoma-derived INS-1 cells demonstrated decreased cell viability accompanied by a significant increase in apoptotic cells. Taken together, these findings suggest that ATP6AP2 plays a role in maintaining cellular homeostasis in insulinoma cells, which could lead to possible therapeutic approaches for endocrine tumors.

Effects of a monoclonal antibody against (pro)renin receptor on gliomagenesis

Glioblastoma is characterized by a strong self-renewal potential and poor differentiated state. We have reported previously that the (pro)renin receptor [(P)RR] is a potential target for glioma therapy by silencing the (P)RR gene. Here, we have examined the effects of a monoclonal antibody against (P)RR on gliomagenesis. Human glioma cell lines (U251MG and U87MG) and a glioma stem cell line (MGG23) were used for the in vitro study. The expressions of the Wnt/β-catenin signaling pathway (Wnt signaling pathway) components and stemness markers were measured by Western blotting. The effects of the (P)RR antibody on cell proliferation, sphere formation, apoptosis and migration were also examined. Subcutaneous xenografts were also examined in nude mice. Treatment with the (P)RR antibody reduced expression of Wnt signaling pathway components and stemness markers. Furthermore, the (P)RR antibody reduced cell proliferation and decreased sphere formation significantly. The treatment also suppressed migration and induced apoptosis. In a subcutaneous xenograft model, systemic administration of the (P)RR antibody reduced tumor volume significantly. These data show that treatment with the (P)RR antibody is a potential therapeutic strategy for treating glioblastoma.

The (Pro)renin Receptor - A Regulatory Nodal Point in Disease Networks

Experimental inhibition of the (pro)renin receptor [(P)RR] is a promising therapeutic strategy in different disease models ranging from cardiorenal to oncological entities. Here, we briefly review the direct protein-protein interaction partners of the (P)RR and the plethora of distinct diseases in which the (P)RR is involved. The first structural work on the (P)RR using AlphaFold, which was recently published by Ebihara et al., is the center of this mini-review since it can mechanistically link the protein-protein interaction level with the pathophysiological level. More detailed insights into the 3D structure of the (P)RR and its interaction domains might guide drug discovery on this novel target. Finally, antibody- and small molecule-based approaches to inhibit the (P)RR are shortly discussed.

Targeting the (pro)renin receptor in cancers: from signaling to pathophysiological effects

Cancer is a major public health problem, currently affecting hundreds of millions of people worldwide, and its clinical results are unpredictable, partly due to the lack of reliable biomarkers of cancer progression. Recently, it has been reported that (pro)renin receptor (PRR), as a new biomarker, plays an important role in different types of cancer, such as colorectal cancer, breast cancer, glioma, aldosterone-producing adenoma, endometrial cancer, urothelial cancer, and pancreatic ductal adenocarcinoma. In order to comprehensively and systematically understand the relationship and role of PRR with various cancers, this review will summarize the current research on targeting PRR in cancer from signaling to pathophysiological effects, including the correlation between PRR/sPRR expression level and different cancers, potential mechanisms regulated by PRR in the progress of cancers, and PRR in cancer treatment. PRR can be a novel and promising biomarker and potential therapeutic target for diagnosis, treatment, and prognosis in cancer, which is worthy of extensive development and application in clinics.

(Pro)renin Receptor Regulates Phosphate Homeostasis in Rats via Releasing Fibroblast Growth Factor-23

Phosphate (Pi) is one of the basic necessities required for sustenance of life and its metabolism largely relies on excretory function of the kidney, a process chiefly under the endocrine control of bone-derived fibroblast growth factor 23 (FGF23). However, knowledge gap exists in understanding the regulatory loop responsible for eliciting phophaturic response to Pi treatment. Here, we reported a novel role of (pro)renin receptor (PRR) in mediating phosphaturic response to Pi treatment via upregulation of FGF23 production. Male Sprague-Dawley rats were pretreated for 5 days via osmotic pump-driven infusion of a PRR antagonist PRO20 or vehicle, and then treated with high Pi (HP) solution as drinking fluid for the last 24 h. PRO20 reduced HP-induced Pi excretion by 42%, accompanied by blunted upregulation of circulating FGF23 and parathyroid hormone (PTH) and downregulation of renal Na/Pi-IIa expression. In cultured osteoblast cells, exposure to HP induced a 1.56-fold increase in FGF23 expression, which was blunted by PRO20 or siRNA against PRR. Together, these results suggest that activation of PRR promotes phosphaturic response through stimulation of FGF23 production and subsequent downregulation of renal Na/Pi-IIa expression.

Identification of a glioma functional network from gene fitness data using machine learning

Glioblastoma multiforme (GBM) is an aggressive form of brain tumours that remains incurable despite recent advances in clinical treatments. Previous studies have focused on sub-categorizing patient samples based on clustering various transcriptomic data. While functional genomics data are rapidly accumulating, there exist opportunities to leverage these data to decipher glioma-associated biomarkers. We sought to implement a systematic approach to integrating data from high throughput CRISPR-Cas9 screening studies with machine learning algorithms to infer a glioma functional network. We demonstrated the network significantly enriched various biological pathways and may play roles in glioma tumorigenesis. From densely connected glioma functional modules, we further predicted 12 potential Wnt/β-catenin signalling pathway targeted genes, including AARSD1, HOXB5, ITGA6, LRRC71, MED19, MED24, METTL11B, SMARCB1, SMARCE1, TAF6L, TENT5A and ZNF281. Cox regression modelling with these targets was significantly associated with glioma overall survival prognosis. Additionally, TRIB2 was identified as a glioma neoplastic cell marker in single-cell RNA-seq of GBM samples. This work establishes novel strategies for constructing functional networks to identify glioma biomarkers for the development of diagnosis and treatment in clinical practice.

Repurposing of Anticancer Stem Cell Drugs in Brain Tumors

Brain tumors in adults may be infrequent when compared with other cancer etiologies, but they remain one of the deadliest with bleak survival rates. Current treatment modalities encompass surgical resection, chemotherapy, and radiotherapy. However, increasing resistance rates are being witnessed, and this has been attributed, in part, to cancer stem cells (CSCs). CSCs are a subpopulation of cancer cells that reside within the tumor bulk and have the capacity for self-renewal and can differentiate and proliferate into multiple cell lineages. Studying those CSCs enables an increasing understanding of carcinogenesis, and targeting CSCs may overcome existing treatment resistance. One approach to weaponize new drugs is to target these CSCs through drug repurposing which entails using drugs, which are Food and Drug Administration-approved and safe for one defined disease, for a new indication. This approach serves to save both time and money that would otherwise be spent in designing a totally new therapy. In this review, we will illustrate drug repurposing strategies that have been used in brain tumors and then further elaborate on how these approaches, specifically those that target the resident CSCs, can help take the field of drug repurposing to a new level.

Elevated (Pro)renin Receptor Expression by Anti-Cancer Drugs, Carboplatin and Paclitaxel, in Cultured Cancer Cells: Possible Involvement of Apoptosis and Autophagy

(Pro)renin receptor [(P)RR] is a component of the renin-angiotensin system and plays an essential role in the activity of vacuolar H⁺-ATPase and autophagy. (P)RR is expressed in cancer cells. However, the relationship among (P)RR, apoptosis and autophagy in the treatment of anti-cancer drugs has not been clarified. The aim of this study was to clarify the effects of anti-cancer drugs with autophagy-promoting activity on (P)RR expression in cancer cells. MCF-7 breast cancer cells and A549 lung cancer cells were treated with carboplatin or paclitaxel, and the expression of (P)RR, apoptosis markers and autophagy markers were assessed by RT-qPCR, western blot analysis and immunocytochemistry. Expression levels of (P)RR mRNA and soluble (P)RR protein were increased by carboplatin or paclitaxel in a dose-dependent manner. Immunofluorescence staining of (P)RR was increased in both MCF-7 and A549 cells treated by carboplatin or paclitaxel. Apoptosis induction was shown by elevated BAX/BCL2 mRNA levels and increased active caspase3-positive cells. Moreover, autophagy induction was confirmed by increased levels of autophagy-associated mRNAs and LC3B-II proteins. (P)RR knockdown by (P)RR-specific siRNA suppressed the cell viability in MCF-7 cells and A549 cells under the treatment of carboplatin or paclitaxel, suggesting that (P)RR deficiency inhibits the proliferation of cancer cells in a pathway different from carboplatin or paclitaxel. The present study showed that the expression of (P)RR mRNA and soluble (P)RR was increased by anti-cancer drugs with autophagy-promoting activity. Upregulated (P)RR and autophagy may constitute a stress adaptation that protects cancer cells from apoptosis.

Functions of the (pro)renin receptor (Atp6ap2) at molecular and system levels: pathological implications in hypertension, renal and brain development, inflammation, and fibrosis

The (pro)renin receptor [(P)RR, Atp6ap2] was initially discovered as a membrane-bound binding partner of prorenin and renin. A soluble (P)RR has additional paracrine effects and is involved in metabolic syndrome and kidney damage. Meanwhile it is clear that most of the effects of the (P)RR are independent of prorenin. In the kidney, (P)RR plays an important role in renal dysfunction by activating proinflammatory and profibrotic molecules. In the brain, (P)RR is expressed in cardiovascular regulatory nuclei and is linked to hypertension. (P)RR is known to be an essential component of the v-ATPase as a key accessory protein and plays an important role in kidney, brain and heart via regulating the pH of the extracellular space and intracellular compartments. V-ATPase and (P)RR together act on WNT and mTOR signalling pathways, which are responsible for cellular homeostasis and autophagy. (P)RR through its role in v-ATPase assembly and function is also important for fast recycling endocytosis by megalin. In the kidney, megalin together with v-ATPase and (P)RR is crucial for endocytic uptake of components of the RAS and their intracellular processing. In the brain, (P)RR, v-ATPases and megalin are important regulators both during development and in the adult. All three proteins are associated with diseases such as XLMR, XMRE, X-linked parkinsonism and epilepsy, cognitive disorders with Parkinsonism, spasticity, intellectual disability, and Alzheimer's Disease which are characterized by impaired neuronal function and/or neuronal loss. The present review focusses on the relevant effects of Atp6ap2 without assigning them necessarily to the RAS. Mechanistically, many effects can be well explained by the role of Atp6ap2 for v-ATPase assembly and function. Furthermore, application of a soluble (P)RR analogue as new therapeutic option is discussed.

The Soluble (Pro)Renin Receptor in Health and Diseases: Foe or Friend?

The (pro)renin receptor (PRR) is a single-transmembrane protein that regulates the local renin-angiotensin system and participates in various intracellular signaling pathways, thus exhibiting a significant physiopathologic relevance in cellular homeostasis. A soluble form of PRR (sPRR) is generated through protease-mediated cleavage of the full-length PRR and secreted into extracellular spaces. Accumulating evidence indicates pivotal biologic functions of sPRR in various physiopathological processes. sPRR may be a novel biomarker for multiple diseases. SIGNIFICANCE STATEMENT: Circulating sPRR concentrations are elevated in patients and animals under various physiopathological conditions. This minireview highlights recent advances in sPRR functions in health and pathophysiological conditions. Results suggest that sPRR may be a novel biomarker for multiple diseases, but further studies are needed to determine the diagnostic value of sPRR.

Serum soluble (pro)renin receptor level as a prognostic factor in patients undergoing maintenance hemodialysis

The (pro)renin receptor [(P)RR)] is a multifunctional protein that is cleaved to generate the soluble (P)RR [s(P)RR], reflecting the status of the tissue renin-angiotensin system and/or activity of the (P)RR. The serum s(P)RR level is associated with arteriosclerosis, independent of other risk factors, in patients undergoing hemodialysis (HD). This study was conducted to investigate whether the s(P)RR level was associated with new-onset cardiovascular events or malignant diseases and poor prognosis in patients undergoing HD. Overall, 258 patients [70 (61–76) years, 146 males] undergoing maintenance HD were prospectively followed up for 60 months. We investigated the relationships between s(P)RR levels and new-onset cardiovascular events/ malignant diseases and mortality during the follow-up period using Cox proportional hazard analyses. The cumulative incidence of new-onset cardiovascular events (P = 0.009) and deaths (P < 0.001), but not of malignant diseases, was significantly greater in patients with higher serum s(P)RR level (≥ 29.8 ng/ml) than in those with lower s(P)RR level (< 29.8 ng/ml). A high serum s(P)RR level was independently correlated with cardiovascular mortality (95% CI 1.001–1.083, P = 0.046). The serum s(P)RR level was associated with cardiovascular events and mortality, thus qualifying as a biomarker for identifying patients requiring intensive care.

The Renin-Angiotensin System in the Tumor Microenvironment of Glioblastoma

Simple Summary

Glioblastoma (GB) is the most aggressive brain cancer in humans. Patient survival outcomes have remained dismal despite intensive research over the past 50 years, with a median overall survival of only 14.6 months. We highlight the critical role of the renin–angiotensin system (RAS) on GB cancer stem cells and the tumor microenvironment which, in turn, influences cancer stem cells in driving tumorigenesis and treatment resistance. We present recent developments and underscore the need for further research into the GB tumor microenvironment. We discuss the novel therapeutic targeting of the RAS using existing commonly available medications and utilizing model systems to further this critical investigation.

Abstract

Glioblastoma (GB) is an aggressive primary brain tumor. Despite intensive research over the past 50 years, little advance has been made to improve the poor outcome, with an overall median survival of 14.6 months following standard treatment. Local recurrence is inevitable due to the quiescent cancer stem cells (CSCs) in GB that co-express stemness-associated markers and components of the renin–angiotensin system (RAS). The dynamic and heterogeneous tumor microenvironment (TME) plays a fundamental role in tumor development, progression, invasiveness, and therapy resistance. There is increasing evidence showing the critical role of the RAS in the TME influencing CSCs via its upstream and downstream pathways. Drugs that alter the hallmarks of cancer by modulating the RAS present a potential new therapeutic alternative or adjunct to conventional treatment of GB. Cerebral and GB organoids may offer a cost-effective method for evaluating the efficacy of RAS-modulating drugs on GB. We review the nexus between the GB TME, CSC niche, and the RAS, and propose re-purposed RAS-modulating drugs as a potential therapeutic alternative or adjunct to current standard therapy for GB.

Novel insights into the interaction between long non-coding RNAs and microRNAs in glioma

Glioma is the most common brain tumor of the central nervous system. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have been identified to play a vital role in the initiation and progression of glioma, including tumor cell proliferation, survival, apoptosis, invasion, and therapy resistance. New documents emerged, which indicated that the interaction between long non-coding RNAs and miRNAs contributes to the tumorigenesis and pathogenesis of glioma. LncRNAs can act as competing for endogenous RNA (ceRNA), and molecular sponge/deregulator in regulating miRNAs. These interactions stimulate different molecular signaling pathways in glioma, including the lncRNAs/miRNAs/Wnt/β-catenin molecular signaling pathway, the lncRNAs/miRNAs/PI3K/AKT/mTOR molecular signaling pathway, the lncRNAs-miRNAs/MAPK kinase molecular signaling pathway, and the lncRNAs/miRNAs/NF-κB molecular signaling pathway. In this paper, the basic roles and molecular interactions of the lncRNAs and miRNAs pathway glioma were summarized to better understand the pathogenesis and tumorigenesis of glioma.

Clinical Implications of (Pro)renin Receptor (PRR) Expression in Renal Tumours

(1) Background: Renal cancer is one of the most frequent malignancies in Western countries, with an unpredictable clinical outcome, partly due to its high heterogeneity and the scarcity of reliable biomarkers of tumour progression. (Pro)renin receptor (PRR) is a novel receptor of the renin–angiotensin system (RAS) that has been associated with the development and progression of some solid tumours by RAS-dependent and -independent mechanisms. (2) Methods: In this study, we analysed the immunohistochemical expression of PRR at the centre and border in a series of 83 clear-cell renal cell (CCRCCs), 19 papillary (PRCC) and 7 chromophobe (ChRCC) renal cell carcinomas, and the benign tumour renal oncocytoma (RO, n = 11). (3) Results: PRR is expressed in all the tumour subtypes, with higher mean staining intensity in ChRCCs and ROs. A high expression of PRR at the tumour centre and at the infiltrative front of CCRCC tissues is significantly associated with high grade, tumour diameter, local invasion and stage, and with high mortality risk by UCLA integrated staging system (UISS) scale. (4) Conclusions: These findings indicate that PRR is associated with the development and progression of renal tumours. Its potential as a novel biomarker for RCC diagnosis/prognosis and as a promising therapeutic target should be taken into account in the future.

Aberrant (pro)renin receptor expression induces genomic instability in pancreatic ductal adenocarcinoma through upregulation of SMARCA5/SNF2H

(Pro)renin receptor [(P)RR] has a role in various diseases, such as cardiovascular and renal disorders and cancer. Aberrant (P)RR expression is prevalent in pancreatic ductal adenocarcinoma (PDAC) which is the most common pancreatic cancer. Here we show whether aberrant expression of (P)RR directly leads to genomic instability in human pancreatic ductal epithelial (HPDE) cells. (P)RR-expressing HPDE cells show obvious cellular atypia. Whole genome sequencing reveals that aberrant (P)RR expression induces large numbers of point mutations and structural variations at the genome level. A (P)RR-expressing cell population exhibits tumour-forming ability, showing both atypical nuclei characterised by distinctive nuclear bodies and chromosomal abnormalities. (P)RR overexpression upregulates SWItch/Sucrose Non-Fermentable (SWI/SNF)-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a, member 5 (SMARCA5) through a direct molecular interaction, which results in the failure of several genomic stability pathways. These data reveal that aberrant (P)RR expression contributes to the early carcinogenesis of PDAC.

Yuki Shibayama et al. find that high expression of (pro)renin receptor [(P)RR] in human pancreatic ductal cells causes increased genomic instability, leading to the development of pancreatic ductal adenocarcinoma. They show that (P)RR exerts its carcinogenic effects through direct binding and activation of the chromatin regulator SMARCA5.

Renin angiotensin system genes are biomarkers for personalized treatment of acute myeloid leukemia with Doxorubicin as well as etoposide

Despite the availability of various treatment protocols, response to therapy in patients with Acute Myeloid Leukemia (AML) remains largely unpredictable. Transcriptomic profiling studies have thus far revealed the presence of molecular subtypes of AML that are not accounted for by standard clinical parameters or by routinely used biomarkers. Such molecular subtypes of AML are predicted to vary in response to chemotherapy or targeted therapy. The Renin-Angiotensin System (RAS) is an important group of proteins that play a critical role in regulating blood pressure, vascular resistance and fluid/electrolyte balance. RAS pathway genes are also known to be present locally in tissues such as the bone marrow, where they play an important role in leukemic hematopoiesis. In this study, we asked if the RAS genes could be utilized to predict drug responses in patients with AML. We show that the combined in silico analysis of up to five RAS genes can reliably predict sensitivity to Doxorubicin as well as Etoposide in AML. The same genes could also predict sensitivity to Doxorubicin when tested in vitro. Additionally, gene set enrichment analysis revealed enrichment of TNF-alpha and type-I IFN response genes among sensitive, and TGF-beta and fibronectin related genes in resistant cancer cells. However, this does not seem to reflect an epithelial to mesenchymal transition per se. We also identified that RAS genes can stratify patients with AML into subtypes with distinct prognosis. Together, our results demonstrate that genes present in RAS are biomarkers for drug sensitivity and the prognostication of AML.

Wnt/beta-catenin and PI3K/Akt/mTOR Signaling Pathways in Glioblastoma: Two Main Targets for Drug Design: A Review

Glioblastoma (GBM) is the most common and malignant astrocytic glioma, accounting for about 90% of all brain tumors with poor prognosis. Despite recent advances in understanding molecular mechanisms of oncogenesis and the improved neuroimaging technologies, surgery, and adjuvant treatments, the clinical prognosis of patients with GBM remains persistently unfavorable. The signaling pathways and the regulation of growth factors of glioblastoma cells are very abnormal. The various signaling pathways have been suggested to be involved in cellular proliferation, invasion, and glioma metastasis. The Wnt signaling pathway with its pleiotropic functions in neurogenesis and stem cell proliferation is implicated in various human cancers, including glioma. In addition, the PI3K/Akt/mTOR pathway is closely related to growth, metabolism, survival, angiogenesis, autophagy, and chemotherapy resistance of GBM. Understanding the mechanisms of GBM's invasion, represented by invasion and migration, is an important tool in designing effective therapeutic interventions. This review will investigate two main signaling pathways in GBM: PI3K/Akt/mTOR and Wnt/beta-catenin signaling pathways.

(Pro)renin receptor/ATP6AP2 is required for autophagy and regulates proliferation in lung adenocarcinoma cells

(Pro)renin receptor ((P)RR)/ ATP6AP2 (ATPase, H⁺ transporting, lysosomal accessory protein 2) functions as an essential accessory subunit of vacuolar H⁺ -ATPase (V-ATPase). V-ATPase is necessary for lysosome function and autophagy. Autophagy is related to cell proliferation, migration and invasion of various cancer cells. In this study, we aim to clarify the relationship between (P)RR and autophagy in lung adenocarcinoma. Expression of (P)RR and Ki-67 (a proliferation marker) was studied in sixty-four adenocarcinoma cases by immunohistochemistry. Lung adenocarcinoma cell line, A549, was transfected with (P)RR-specific siRNA. Autophagy inhibitors, bafilomycin A1 and chloroquine, were used as positive controls. Cell proliferation and migration were measured by WST-8 assay and wound healing assay. Autophagosome markers, p62 and LC3, were analyzed by RT-qPCR, Western blot and immunocytochemistry. Immunohistochemistry showed that (P)RR was expressed in all adenocarcinoma tissues. The intensity of (P)RR immunoreactivity was significantly associated with Ki-67. Treatment of (P)RR-specific siRNA suppressed (P)RR expression and significantly reduced cell proliferation and migration as did the autophagy inhibitors. Western blot and immunocytochemistry showed that (P)RR-specific siRNA, as well as the autophagy inhibitors, induced p62 and LC3 accumulation in cytoplasmic granules. These results suggest that (P)RR is involved in cell proliferation and progression of lung adenocarcinoma via regulating autophagy.

ATP6AP2 is Overexpressed in Breast Cancer and Promotes Breast Cancer Progression

Background

Adenosine triphosphatase H+ transporting accessory protein 2 (ATP6AP2), also known as (pro)renin receptor, is implicated in tumorigenesis and the progression of several types of cancer. This study investigated the role of ATP6AP2 in breast cancer.

Methods

UALCAN and ONCOMINE datasets were utilized to compare transcript levels of ATP6AP2 in breast cancer and normal tissues. GOBO datasets were applied to examine ATP6AP2 expression in different breast cancer cell lines. We used the cBioPortal website to explore the gene alterations and copy number alterations of ATP6AP2 in breast cancer. Cell Counting Kit-8 and transwell assays were conducted to evaluate ATP6AP2 function in MCF-7 breast cancer cells. Finally, we used the cBioPortal website to establish the interaction network of ATP6AP2 in breast cancer and performed functional enrichment analysis based on Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways.

Results

ATP6AP2 was overexpressed in breast cancer tissues and breast cancer cell lines in the UALCAN, ONCOMINE, and GOBO datasets. The major type of ATP6AP2 alteration was mRNA upregulation. Moreover, ATP6AP2 was most highly expressed in luminal type breast cancer. Finally, ATP6AP2 knockdown reduced MCF-7 cell proliferation, invasion and migration. Functional enrichment analysis suggested that ATP6AP2 regulates several cancer-related pathways, especially the Wnt/β-catenin signaling pathway.

Conclusion

Applying multi-dimensional analytical methods, we demonstrate that ATP6AP2 is upregulated in breast cancer and may promote its development and progression.

The interaction partners of (pro)renin receptor in the distal nephron

The (pro)renin receptor (PRR), a key regulator of intrarenal renin-angiotensin system (RAS), is predominantly presented in podocytes, proximal tubules, distal convoluted tubules, and the apical membrane of collecting duct A-type intercalated cells, and plays a crucial role in hypertension, cardiovascular disease, kidney disease, and fluid homeostasis. In addition to its well-known renin-regulatory function, increasing evidence suggests PRR can also act in a variety of intracellular signaling cascades independently of RAS in the renal medulla, including Wnt/β-catenin signaling, cyclooxygenase-2 (COX-2)/prostaglandin E₂ (PGE₂ ) signaling, and the apelinergic system, and work as a component of the vacuolar H⁺ -ATPase. PRR and these pathways regulate the expression/activity of each other that controlling blood pressure and renal functions. In this review, we highlight recent findings regarding the antagonistic interaction between PRR and ELABELA/apelin, the mutually stimulatory relationship between PRR and COX-2/PGE₂ or Wnt/β-catenin signaling in the renal medulla, and their involvement in the regulation of intrarenal RAS thereby control blood pressure, renal injury, and urine concentrating ability in health and patho-physiological conditions. We also highlight the latest progress in the involvement of PRR for the vacuolar H⁺ -ATPase activity.

Antiproliferative Effects of Monoclonal Antibodies against (Pro)Renin Receptor in Pancreatic Ductal Adenocarcinoma

We previously reported that silencing of the PRR gene, which encodes the (pro)renin receptor [(P)RR], significantly reduced Wnt/β-catenin-dependent development of pancreatic ductal adenocarcinoma (PDAC). Here, we examined the effects of a panel of blocking mAbs directed against the (P)RR extracellular domain on proliferation of the human PDAC cell lines PK-1 and PANC-1 in vitro and in vivo We observed that four rat anti-(P)RR mAbs induced accumulation of cells in the G₀-G₁-phase of the cell cycle and significantly reduced proliferation in vitro concomitant with an attenuation of Wnt/β-catenin signaling. Systemic administration of the anti-(P)RR mAbs to nude mice bearing subcutaneous PK-1 xenografts significantly decreased tumor expression of active β-catenin and the proliferation marker Ki-67, and reduced tumor growth. In contrast, treatment with the handle region peptide of (pro)renin did not inhibit tumor growth in vitro or in vivo, indicating that the effects of the anti-(P)RR mAbs were independent of the renin-angiotensin system. These data indicate that mAbs against human (P)RR can suppress PDAC cell proliferation by hindering activation of the Wnt/β-catenin signaling pathway. Thus, mAb-mediated (P)RR blockade could be an attractive therapeutic strategy for PDAC.

Increased soluble (pro)renin receptor protein by autophagy inhibition in cultured cancer cells

(Pro)renin receptor ((P)RR) regulates the renin-angiotensin system and functions as an essential accessory subunit of vacuolar H+ -ATPase. There is accumulating evidence that shows close relationship between (P)RR and autophagy. Soluble (P)RR consisting of the extracellular domain of (P)RR is generated from (P)RR by proteolytic enzymes. The aim of the present study was to clarify the influence of autophagy inhibition on soluble (P)RR expression in cancer cells. Autophagy was inhibited by treatment of bafilomycin A1 or chloroquine in MCF-7 and A549 cells for 72 hr. Western blot analysis showed that protein levels of soluble (P)RR were markedly elevated by autophagy inhibition, whereas no noticeable increases were observed in full-length (P)RR. Secretion of soluble (P)RR into the medium was increased dose-dependently by bafilomycin A1 or chloroquine. Autophagy inhibition was confirmed by enhanced accumulation of autophagy-related proteins, LC3, p62 and LAMP1 in intracellular vesicles. Increased amount of soluble (P)RR by autophagy inhibition was decreased by site-1 protease inhibitor, whereas no noticeable increase in site-1 protease immunoreactivity was observed in cells with autophagy inhibition by immunocytochemistry. These findings suggest that soluble (P)RR protein accumulates by autophagy inhibition, possibly because of the reduced degradation of soluble (P)RR in the intracellular vesicles during autophagy inhibition.

(Pro)renin receptor contributes to hypoxia/reoxygenation-induced apoptosis and autophagy in myocardial cells via the beta-catenin signaling pathway

(Pro)renin receptor (PRR) contributes to regulating many physiological and pathological processes; however, the role of PRR-mediated signaling pathways in myocardial ischemia/reperfusion injury (IRI) remains unclear. In this study, we used an in vitro model of hypoxia/reoxygenation (H/R) to mimic IRI and carried out PRR knockdown by siRNA and PRR overexpression using cDNA in H9c2 cells. Cell proliferation activity was examined by MTT and Cell Counting Kit-8 (CCK-8) assays. Apoptosis-related factors, autophagy markers and beta-catenin pathway activity were assessed by real-time PCR and western blotting. After 24 h of hypoxia followed by 2 h of reoxygenation, the expression levels of PRR, LC3B-I/II, Beclin1, cleaved caspase-3, cleaved caspase-9 and Bax were upregulated, suggesting that apoptosis and autophagy were increased in H9c2 cells. Contrary to the effects of PRR downregulation, the overexpression of PRR inhibited proliferation, induced apoptosis, increased the expression of pro-apoptotic factors and autophagy markers, and promoted activation of the beta-catenin pathway. Furthermore, all these effects were reversed by treatment with the beta-catenin antagonist DKK-1. Thus, we concluded that PRR activation can trigger H/R-induced apoptosis and autophagy in H9c2 cells through the beta-catenin signaling pathway, which may provide new therapeutic targets for the prevention and treatment of myocardial IRI.

The (pro)renin receptor: a novel biomarker and potential therapeutic target for various cancers

BACKGROUND

The (pro) renin receptor ((P)RR) plays important roles in various pathways, such as the Wnt/β-catenin, renin-angiotensin system (RAS), MAPK/ERK and PI3K/AKT/mTOR pathways, that are involved in a wide range of physiological and pathological processes incorporating the tumorigenesis. However, our knowledge about (P) RR was mostly limited to its roles in cardiovascular and renal physiological functions and diseases. In the past 5 years, however, compelling evidence has revealed that (P) RR is aberrantly expressed in and contributes to the development of various cancers by different means. For instance, (P) RR was recently demonstrated to induce the oncogenesis of pancreatic, colorectal and brain cancers via the Wnt signaling, while promote the endometrial cancer and glioblastoma through the RAS.

METHODS

Combining with the deep analysis of big data from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases, this review updates and summarizes the recent studies about the newly recognized roles of (P) RR in the pathophysiological processes of cancer development and its detailed functions through related pathways, as well as the novel research progress of (P) RR in related fields including the development and application of soluble (P) RR detection kit and monoclonal (P) RR antibody.

RESULTS

This review provides an overview of the essential roles of (P) RR in the tumorigenesis and progression of various cancers and offers a translational outlook for the future research and clinical practices.

CONCLUSION

(P) RR in the tumor tissues and/or body fluids of patients may be a novel and promising biomarker and potential therapeutic target for diagnosis, treatment and prognosis prediction in various cancers. Video Abstract.

Recent Research Advances in Renin-Angiotensin-Aldosterone System Receptors

PURPOSE OF REVIEW

The renin-angiotensin-aldosterone system (RAAS) plays important roles in regulating blood pressure and body fluid, which contributes to the pathophysiology of hypertension and cardiovascular/renal diseases. However, accumulating evidence has further revealed the complexity of this signal transduction system, including direct interactions with other receptors and proteins. This review focuses on recent research advances in RAAS with an emphasis on its receptors.

RECENT FINDINGS

Both systemically and locally produced angiotensin II (Ang II) bind to Ang II type 1 receptor (AT1R) and elicit strong biological functions. Recent studies have shown that Ang II-induced activation of Ang II type 2 receptor (AT2R) elicits the opposite functions to those of AT1R. However, accumulating evidence has now expanded the components of RAAS, including (pro)renin receptor, angiotensin-converting enzyme 2, angiotensin 1-7, and Mas receptor. In addition, the signal transductions of AT1R and AT2R are regulated by not only Ang II but also its receptor-associated proteins such as AT1R-associated protein and AT2R-interacting protein. Recent studies have indicated that inappropriate activation of local mineralocorticoid receptor contributes to cardiovascular and renal tissue injuries through aldosterone-dependent and -independent mechanisms. Since the mechanisms of RAAS signal transduction still remain to be elucidated, further investigations are necessary to explore novel molecular mechanisms of the RAAS, which will provide alternative therapeutic agents other than existing RAAS blockers.

The (pro)renin receptor in health and disease

The (pro)renin receptor ((P)RR) was first identified as a single-transmembrane receptor in human kidneys and initially attracted attention owing to its potential role as a regulator of the tissue renin-angiotensin system (RAS). Subsequent studies found that the (P)RR is widely distributed in organs throughout the body, including the kidneys, heart, brain, eyes, placenta and the immune system, and has multifaceted functions in vivo. The (P)RR has roles in various physiological processes, such as the cell cycle, autophagy, acid-base balance, energy metabolism, embryonic development, T cell homeostasis, water balance, blood pressure regulation, cardiac remodelling and maintenance of podocyte structure. These roles of the (P)RR are mediated by its effects on important biological systems and pathways including the tissue RAS, vacuolar H⁺-ATPase, Wnt, partitioning defective homologue (Par) and tyrosine phosphorylation. In addition, the (P)RR has been reported to contribute to the pathogenesis of diseases such as fibrosis, hypertension, pre-eclampsia, diabetic microangiopathy, acute kidney injury, cardiovascular disease, cancer and obesity. Current evidence suggests that the (P)RR has key roles in the normal development and maintenance of vital organs and that dysfunction of the (P)RR is associated with diseases that are characterized by a disruption of the homeostasis of physiological functions.

Meningioma Tumor Microenvironment

The tumor microenvironment consists of noncancerous cells, such as immune cells and fibroblasts, and the proteins produced by these cells as well as the extracellular matrix components in the environment around a tumor. Tumor influences the behavior of the cells present in the surrounding environment, while the cells in the tumor microenvironment modulate the evolution of the tumor. Little is known about the microenvironment of meningioma, the most common benign intracranial tumor. Here, we review the current knowledge of the tumor microenvironment of meningioma and discusses its importance in meningioma tumorigenesis as well as in the designation of novel therapeutic approaches.

EXPRESSION OF THE RENIN-ANGIOTENSIN SYSTEM COMPONENTS IN ONCOLOGIC DISEASES

The literature devoted to changes in the expression of the renin-angiotensin system (RAS) proteins of cancer cells was analyzed. The dynamics of RAS protein expression in malignant tumors and the possible role of epigenetic mechanisms in these processes are briefly reviewed. Through research of the epigenetic mechanisms in cancer, principally new techniques for their correction based on the use of selective regulatory systems of covalent modification of histone proteins (for example, deacetylase inhibitor) and microRNA synthesis technologies have been developed. Literature data show promising pharmacological correction of epigenetic modification of chromatin in the treatment of cancer.

Use of Genome-Scale Integrated Analysis to Identify Key Genes and Potential Molecular Mechanisms in Recurrence of Lower-Grade Brain Glioma

BACKGROUND The aim of this study was to identify gene signals for lower-grade glioma (LGG) and to assess their potential as recurrence biomarkers. MATERIAL AND METHODS An LGG-related mRNA sequencing dataset was downloaded from The Cancer Genome Atlas (TCGA) Informix. Multiple bioinformatics analysis methods were used to identify key genes and potential molecular mechanisms in recurrence of LGG. RESULTS A total of 326 differentially-expressed genes (DEGs), were identified from 511 primary LGG tumor and 18 recurrent samples. Gene ontology (GO) analysis revealed that the DEGs were implicated in cell differentiation, neuron differentiation, negative regulation of neuron differentiation, and cell proliferation in the forebrain. The Kyoto Encyclopedia of Genes and Genomes (KEGG) database suggests that DEGs are associated with proteoglycans in cancer, the Wnt signaling pathway, ECM-receptor interaction, the PI3K-Akt signaling pathway, transcriptional deregulation in cancer, and the Hippo signaling pathway. The hub DEGs in the protein-protein interaction network are apolipoprotein A2 (APOA2), collagen type III alpha 1 chain (COL3A1), collagen type I alpha 1 chain (COL1A1), tyrosinase (TYR), collagen type I alpha 2 chain (COL1A2), neurotensin (NTS), collagen type V alpha 1 chain (COL5A1), poly(A) polymerase beta (PAPOLB), insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), and anomalous homeobox (ANHX). GSEA revealed that the following biological processes may associated with LGG recurrence: cell cycle, DNA replication and repair, regulation of apoptosis, neuronal differentiation, and Wnt signaling pathway. CONCLUSIONS Our study demonstrated that hub DEGs may assist in the molecular understanding of LGG recurrence. These findings still need further molecular studies to identify the assignment of DEGs in LGG.

Expression of Components of the Renin-Angiotensin System by the Putative Stem Cell Population Within WHO Grade I Meningioma

Aim: We have recently demonstrated a putative stem cell population within WHO grade I meningioma (MG) that expressed embryonic stem cell (ESC) markers OCT4, NANOG, SOX2, KLF4 and c-MYC, localized to the endothelial and pericyte layers of the microvessels. There is increasing recognition that the renin-angiotensin system (RAS) plays a critical role in stem cell biology and tumorigenesis. This study investigated the expression of components of the RAS: pro-renin receptor (PRR), angiotensin converting enzyme (ACE), angiotensin II receptor 1 (ATIIR1), and angiotensin II receptor 2 (ATIIR2) on the putative stem cell population on the microvessels of WHO grade I MG.

Methods: 3,3-Diaminobenzidine (DAB) immunohistochemical (IHC) staining was performed on WHO grade I MG tissue samples from 11 patients for PRR, ACE, ATIIR1, and ATIIR2. Two of the MG samples subjected to DAB IHC staining underwent immunofluorescence (IF) IHC staining to investigate co-expression of each of these components of the RAS in using combinations of CD34 and ESC marker SOX2 or OCT4. NanoString mRNA expression analysis and Western blotting (WB), were performed on six snap-frozen MG tissue samples to confirm mRNA and protein expression of these proteins, respectively.

Results: DAB IHC staining demonstrated expression of PRR, ACE, ATIIR1, and ATIIR2 within all 11 MG tissue samples. WB and NanoString mRNA analyses, confirmed protein and mRNA expression of these proteins, respectively. IF IHC staining showed PRR, ATIIR1 and ATIIR2 were localized to the OCT4⁺ and SOX2⁺ endothelium and the pericyte layer of MG while ACE was localized to the OCT4⁺ endothelium of the microvesels.

Conclusion: The novel finding of the expression of PRR, ACE, ATIIR1, and ATIIR2 on the putative stem cell population on the microvessels of WHO grade I MG, suggests that these stem cells may be a potential therapeutic target by manipulation of the RAS.

(Pro)renin receptor promotes colorectal cancer through the Wnt/beta-catenin signalling pathway despite constitutive pathway component mutations

Background

Although constitutive activating mutations in the Wnt/β-catenin signalling pathway are important for colorectal cancer development, canonical signalling through Wnt ligands is essential for β-catenin activation. Here, we investigated the role of (pro)renin receptor ((P)RR), a component of the Wnt receptor complex, in the pathogenesis of colorectal cancer.

Methods

(P)RR silencing was performed in human colorectal cancer cells containing constitutive activating mutations in the Wnt/β-catenin pathway. (P)RR overexpression was induced in normal colon epithelial cells. Protein and mRNA levels of pathway components were detected, and Wnt signalling activity was measured using a β-catenin reporter. Cell proliferative activity and apoptosis were evaluated using WST-1 assay and flow cytometry. Xenografts were induced in nude mice.

Results

(P)RR expression was greater in colorectal cancer tissues and cells than in normal colorectal samples. Patients with strong (P)RR expression took more proportion in groups with poorly-differentiated, advanced and rapidly-progressing cancers. (P)RR silencing attenuated the pathway in colorectal cancer cells, impaired their proliferation in vitro and vivo. (P)RR overexpression enhanced the pathway and proliferation of normal colon epithelial cells.

Conclusions

Aberrant (P)RR expression promotes colorectal cancer through the Wnt/β-catenin signalling pathway despite constitutive pathway-activating mutations. (P)RR is a potential diagnostic and therapeutic target for colorectal cancer.

Precision-guided long-acting analgesia by Gel-immobilized bupivacaine-loaded microsphere

Peripheral nerve blockade (PNB) is a conventional strategy for the management of acute postoperative pain. However, the short duration of the associated analgesia and the potential systemic toxicity due to the low molecular weights of local anesthetics limit their application. Methods: An in situ forming injectable Gel-microsphere (Gel-MS) system consisting of PLGA-PEG-PLGA Gel (Gel) and Gel-immobilized bupivacaine-loaded microsphere (MS/BUP) was prepared for precision-guided long-acting analgesia. A series of in vitro characterizations, such as scanning electron microscopy, rheology analysis, confocal laser scanning microscopy, drug release, and erosion and degradation, were carried out. After that, the in vivo analgesia effect of the Gel-MS system, the immobilization effect of Gel on the MS, and biocompatibility of the system were evaluated using a sciatic nerve block model. Results: The BUP release from the Gel-MS system was regulated by both the inner MS and the outer Gel matrix, demonstrating sustained BUP release in vitro for several days without an initial burst release. More importantly, incorporation of the Gel immobilized the MS and hindered the diffusion of MS from the injection site because of its in situ property, which contributed to a high local drug concentration and prevented systemic side effects. In vivo, a single injection of Gel-MS/BUP allowed rats to maintain sensory and motor blockade significantly longer than treatment with MS/BUP (P < 0.01) or BUP-loaded Gel (Gel-BUP, P < 0.01). Histopathological results demonstrated the excellent biodegradability and biocompatibility of the Gel-MS system without neurotoxicity. Conclusion: This precision-guided long-acting analgesia, which provides an in situ and sustained release of BUP, is a promising strategy for long-acting analgesia, and could represent a potential alternative for clinical pain management.