The Opposing Roles of PIK3R1/p85α and PIK3R2/p85β in Cancer

Ethoxy-erianin phosphate inhibits angiogenesis in colorectal cancer by regulating the TMPO-AS1/miR-126-3p/PIK3R2 axis and inactivating the PI3k/AKT signaling pathway

Colorectal cancer (CRC) is the third most common malignancy, with increasing prevalence and mortality. How the ethoxy-erianin phosphate (EBTP) mediates CRC development remains unclear. Therefore, the current study evaluated the effects of EBTP on the proliferation, migration, and angiogenesis of CRC cells using CCK-8, Wound-healing, Transwell, and Tube formation assays. RNA sequencing and molecular docking techniques helped predict that EBTP could inhibit angiogenesis by regulating PIK3R2 expression while clarifying the mechanism behind EBTP-mediated CRC angiogenesis. Subsequently, several in vitro experiments indicated that PIK3R2 overexpression significantly improved the proliferation, migration, and angiogenesis of CRC cells while knocking down PIK3R2 expression inhibited their proliferation, migration, and angiogenesis. Simultaneously, PIK3R2 expression in CRC cells gradually decreased with increased EBTP concentration and action duration. Moreover, PIK3R2 overexpression in CRC cells could reverse the inhibitory EBTP effect in angiogenesis. Mouse experiments also depicted that EBTP inhibited CRC angiogenesis by down-regulating PIK3R2 expression. In addition, EBTP could inhibit PI3K/AKT pathway activity and indirectly control PIK3R2 expression through the lncRNA TMPO-AS1/miR-126-3p axis. Our findings highlighted that EBTP could inhibit CRC angiogenesis using the TMPO-AS1/miR-126-3p/PIK3R2/PI3k/AKT axis, providing a novel strategy for anti-angiogenic therapy in CRC.

Development of a TLR-Based Model That Can Predict Prognosis, Tumor Microenvironment, and Drug Response for Esophageal Squamous Cell Carcinoma

The toll-like receptor (TLR) family is an important class of proteins involved in the immune response. However, little is known about the association between TLRs and Esophageal squamous cell cancer (ESCC). We explored differentially expressed genes (DEGs) between ESCC and esophagus tissues in TCGA and GTEx database. By taking the intersection with TLR gene set and using univariate Cox analysis and multivariate Cox regression analysis to discriminate the hub genes, we created a TLR-prognostic model. Our model separated patients with ESCC into high- and low-risk score (RS) groups. Prognostic analysis was performed with Kaplan-Meier curves. The two groups were also compared regarding tumor immune microenvironment and drug sensitivity. Six hub genes (including CD36, LGR4, MAP2K3, NINJ1, PIK3R1, and TRAF3) were screened to construct a TLR-prognostic model. High-RS group had a worse survival (p < 0.01), lower immune checkpoint expression (p < 0.05), immune cell abundance (p < 0.05) and decreased sensitivity to Epirubicin (p < 0.001), 5-fluorouracil (p < 0.0001), Sorafenib (p < 0.01) and Oxaliplatin (p < 0.05). We constructed a TLR-based model, which could be used to assess the prognosis of patients with ESCC, provide new insights into drug treatment for ESCC patients and investigate the TME and drug response.

A potential therapeutic strategy based on acute oxidative stress induction for wild-type NRF2/KEAP1 lung squamous cell carcinoma

Extensive efforts have been conducted in the search for new targetable drivers of lung squamous cell carcinoma (LUSC); to date, however, candidates remain mostly unsuccessful. One of the oncogenic pathways frequently found to be active in LUSC is NFE2L2 (NRF2 transcription factor), the levels of which are regulated by KEAP1. Mutations in NFE2L2 or KEAP1 trigger NRF2 activation, an essential protector against reactive oxygen species (ROS). We hypothesized that the frequency of NRF2 activation in LUSC (∼35 %) may reflect a sensitivity of LUSC to ROS. Results from this study reveal that whereas tumors containing active forms of NRF2 were protected, ROS induction in wild-type NFE2L2/KEAP1 LUSC cells triggered ferroptosis. The mechanism of ROS action in normal-NRF2 LUSC cells involved transient NRF2 activation, miR-126-3p/miR-126-5p upregulation, and reduction of p85β and SETD5 levels. SETD5 levels reduction triggered pentose pathway gene levels increase to toxic values. Simultaneous depletion of p85βPI3K and SETD5 triggered LUSC cell death, while p85βPI3K and SETD5 overexpression rescued survival of ROS-treated normal-NRF2 LUSC cells. This shows that the cascade involving NRF2 > miR-126-3p, miR-126-5p > p85βPI3K and SETD5 is responsible for ROS-induced cell death in normal-NRF2 LUSC. Transient ROS-induced cell death is shown in 3D spheroids, patient-derived organoids, and in xenografts of wild-type NFE2L2/KEAP1 LUSC cells, supporting the potential of acute local ROS induction as a therapeutic strategy for LUSC patients with normal-NRF2.

Unveiling the role of PIK3R1 in cancer: A comprehensive review of regulatory signaling and therapeutic implications

Phosphoinositide 3-kinase (PI3K) is responsible for phosphorylating phosphoinositides to generate secondary signaling molecules crucial for regulating various cellular processes, including cell growth, survival, and metabolism. The PI3K is a heterodimeric enzyme complex comprising of a catalytic subunit (p110α, p110β, or p110δ) and a regulatory subunit (p85). The binding of the regulatory subunit, p85, with the catalytic subunit, p110, forms an integral component of the PI3K enzyme. PIK3R1 (phosphoinositide-3-kinase regulatory subunit 1) belongs to class IA of the PI3K family. PIK3R1 exhibits structural complexity due to alternative splicing, giving rise to distinct isoforms, prominently p85α and p55α. While the primary p85α isoform comprises multiple domains, including Src homology 3 (SH3) domains, a Breakpoint Cluster Region Homology (BH) domain, and Src homology 2 (SH2) domains (iSH2 and nSH2), the shorter isoform, p55α, lacks certain domains present in p85α. In this review, we will highlight the intricate regulatory mechanisms governing PI3K signaling along with the impact of PIK3R1 alterations on cellular processes. We will further delve into the clinical significance of PIK3R1 mutations in various cancer types and their implications for prognosis and treatment outcomes. Additionally, we will discuss the evolving landscape of targeted therapies aimed at modulating PI3K-associated pathways. Overall, this review will provide insights into the dynamic interplay of PIK3R1 in cancer, fostering advancements in precision medicine and the development of targeted interventions.

5-Fluorouracil in Combination with Calcium Carbonate Nanoparticles Loaded with Antioxidant Thymoquinone against Colon Cancer: Synergistically Therapeutic Potential and Underlying Molecular Mechanism

Colon cancer is the third most common cancer worldwide, with high mortality. Adverse side effects and chemoresistance of the first-line chemotherapy 5-fluorouracil (5-FU) have promoted the widespread use of combination therapies. Thymoquinone (TQ) is a natural compound with potent antioxidant activity. Loading antioxidants into nano delivery systems has been a major advance in enhancing their bioavailability to improve clinical application. Hence, this study aimed to prepare the optimal TQ-loaded calcium carbonate nanoparticles (TQ-CaCO3 NPs) and investigate their therapeutic potential and underlying molecular mechanisms of TQ-CaCO3 NPs in combination with 5-FU against colon cancer. Firstly, we developed purely aragonite CaCO3 NPs with a facile mechanical ball-milling method. The pH-sensitive and biocompatible TQ-CaCO3 NPs with sustained release properties were prepared using the optimal synthesized method (a high-speed homogenizer). The in vitro study revealed that the combination of TQ-CaCO3 NPs (15 μM) and 5-FU (7.5 μM) inhibited CT26 cell proliferation and migration, induced cell apoptosis and cell cycle arrest in the G0/G1 phase, and suppressed the CT26 spheroid growth, exhibiting a synergistic effect. Finally, network pharmacology and molecular docking results indicated the potential targets and crucial signaling pathways of TQ-CaCO3 NPs in combination with 5-FU against colon cancer. Therefore, TQ-CaCO3 NPs combined with 5-FU could enhance the anti-colon cancer effects of 5-FU with broader therapeutic targets, warranting further application for colon cancer treatment.

PI3K couples long-term synaptic potentiation with cofilin recruitment and actin polymerization in dendritic spines via its regulatory subunit p85α

Long-term synaptic plasticity is typically associated with morphological changes in synaptic connections. However, the molecular mechanisms coupling functional and structural aspects of synaptic plasticity are still poorly defined. The catalytic activity of type I phosphoinositide-3-kinase (PI3K) is required for specific forms of synaptic plasticity, such as NMDA receptor-dependent long-term potentiation (LTP) and mGluR-dependent long-term depression (LTD). On the other hand, PI3K signaling has been linked to neuronal growth and synapse formation. Consequently, PI3Ks are promising candidates to coordinate changes in synaptic strength with structural remodeling of synapses. To investigate this issue, we targeted individual regulatory subunits of type I PI3Ks in hippocampal neurons and employed a combination of electrophysiological, biochemical and imaging techniques to assess their role in synaptic plasticity. We found that a particular regulatory isoform, p85α, is selectively required for LTP. This specificity is based on its BH domain, which engages the small GTPases Rac1 and Cdc42, critical regulators of the actin cytoskeleton. Moreover, cofilin, a key regulator of actin dynamics that accumulates in dendritic spines after LTP induction, failed to do so in the absence of p85α or when its BH domain was overexpressed as a dominant negative construct. Finally, in agreement with this convergence on actin regulatory mechanisms, the presence of p85α in the PI3K complex determined the extent of actin polymerization in dendritic spines during LTP. Therefore, this study reveals a molecular mechanism linking structural and functional synaptic plasticity through the coordinate action of PI3K catalytic activity and a specific isoform of the regulatory subunits.

Targeting PI3K family with small-molecule inhibitors in cancer therapy: current clinical status and future directions

The Phosphatidylinositol-3-kinase (PI3K) family is well-known to comprise three classes of intracellular enzymes. Class I PI3Ks primarily function in signaling by responding to cell surface receptor stimulation, while class II and III are more involved in membrane transport. Under normal physiological conditions, the PI3K signaling network orchestrates cell growth, division, migration and survival. Aberrant activation of the PI3K signaling pathway disrupts cellular activity and metabolism, often marking the onset of cancer. Currently, the Food and Drug Administration (FDA) has approved the clinical use of five class I PI3K inhibitors. These small-molecule inhibitors, which exhibit varying selectivity for different class I PI3K family members, are primarily used in the treatment of breast cancer and hematologic malignancies. Therefore, the development of novel class I PI3K inhibitors has been a prominent research focus in the field of oncology, aiming to enhance potential therapeutic selectivity and effectiveness. In this review, we summarize the specific structures of PI3Ks and their functional roles in cancer progression. Additionally, we critically evaluate small molecule inhibitors that target class I PI3K, with a particular focus on their clinical applications in cancer treatment. Moreover, we aim to analyze therapeutic approaches for different types of cancers marked by aberrant PI3K activation and to identify potential molecular targets amenable to intervention with small-molecule inhibitors. Ultimately, we propose future directions for the development of therapeutic strategies that optimize cancer treatment outcomes by modulating the PI3K family.

Lnc-PIK3R1, transcriptionally suppressed by YY1, inhibits hepatocellular carcinoma progression via the Lnc-PIK3R1/miR-1286/GSK3β axis

Hepatocellular carcinoma (HCC) poses a significant threat due to its highly aggressive and high recurrence characteristics, necessitating urgent advances in diagnostic and therapeutic approaches. Long non-coding RNAs exert vital roles in HCC tumorigenesis, however the mechanisms of their expression regulation and functions are not fully elucidated yet. Herein, we identify that a novel tumor suppressor 'lnc-PIK3R1' was significantly downregulated in HCC tissues, which was correlated with poor prognosis. Functionally, lnc-PIK3R1 played tumor suppressor roles to inhibit the proliferation and mobility of HCC cells, and to impede the distant implantation of xenograft in mice. Mechanistic studies revealed that lnc-PIK3R1 interacted with miR-1286 and alleviated the repression on GSK3B by miR-1286. Notably, pharmacological inhibition of GSK3β compromised the tumor suppression effect by lnc-PIK3R1, confirming their functional relevance. Moreover, we identified that oncogenic YY1 acts as a specific transcriptional repressor to downregulate the expression of lnc-PIK3R1 in HCC. In summary, this study highlights the tumor-suppressive effect of lnc-PIK3R1, and provides new insights into the regulation of GSK3β expression in HCC, which would benefit the development of innovative intervention strategies for HCC.

Neuroprotective effects of total phenolics from Hemerocallis citrina Baroni leaves through the PI3K/AKT pathway

Neurological injury, as a major pathogenic mechanism in depression, holds significant importance in the research and development of antidepressant drugs. Hemerocallis citrina Baroni (H. citrina), referred to as "Forgetting Sadness Grass," has been confirmed to possess remarkable neuroprotective effects. Studies have identified that the total phenolics in H. citrina Baroni leaves (HLTP) consist of flavonoids and phenolic acids and numerous studies have substantiated the neuroprotective effects of them. Based on this, we propose that HLTP may possess neuroprotective properties. To confirm this hypothesis, we initially employed network pharmacology techniques to predict potential targets for the neuroprotective effects of HLTP based on the Swiss Target Prediction database. GO and KEGG analyses were conducted to predict potential pathways, and a component-target-pathway network was constructed. Molecular docking experiments were then performed to analyze the binding abilities of the selected active components with the main targets. Furthermore, we validated the neuroprotective effects of HLTP and key targets selected through network pharmacology using a corticosterone-induced PC12 neuronal cell damage model. Network pharmacology research has identified that in the HLTP, Quercetin, Rutin, Apigenin, and Isoquercitrin are potential active components that may exert neuroprotective effects by modulating key targets such as AKT1, TNF, TP53, and CASP3 through crucial pathways including PI3K/AKT and apoptosis. Molecular docking revealed that 4-O-Caffeoylquinic acid, 5-O-Caffeoylshikimic acid, 4-p-Coumaroylquinic acid, and 5-O-Feruloylquinic acid exhibit low binding energies with key targets. Particularly, 4-O-Caffeoylquinic acid forms stable binding through hydrogen bonding with residues such as LYS389, GLU49, GLN47, LYS30, ASP44, and GLU40 in AKT1. PC12 cells were stimulated with 200 μmol/L Corticosterone (Cort) for 24 h, and then treated with 50, 100 and 200 μg/mL of HLTP for 24 h. The cell viability of damaged cells were significantly increased in a dose-dependent manner by 9.50%, 10.42% and 21.25%, respectively (P < 0.01). Western blot analysis confirmed that HLTP significantly (P < 0.01) increased the protein expression of PI3K and AKT by 15.24%, 30.44%, 41.03%, and 21.78%, 43.63%, 12.86%, respectively. In addition, through biochemical method, flow cytometry and WB analysis, we found that different concentrations of HLTP can all improve cell damage by reducing ROS, MDA, Ca2+, Cyt-C, Caspase-3, TNF-α and IL-1β, and increasing SOD, CAT, MMP, Bcl-2/Bax and IL-10. In particular, the HLTP at 200 μg/mL, compared with the Model group, decreased by 140.2%, 54.66%, 51.34%, 65.26%, 40.32%, 63.87%, and 55.38%, and increased by 39.65%, 35.45%, 38.38%, 28.54%, and 39.98%, respectively. Through the above experiments, we verified that HLTP may exert neuroprotective effects by mediating the PI3K/AKT signaling pathway to counteract oxidative stress damage, improve mitochondrial dysfunction, and alleviate inflammatory injury.

The mechanism of action of myricetin against lung adenocarcinoma based on bioinformatics, in silico and in vitro experiments

Myricetin is a natural flavonoid with anti-cancer and anti-inflammatory effects, but its mechanism for treating lung adenocarcinoma (LUAD) remains unclearly. Therefore, bioinformatics, in silico and in vitro experiments were employed to elucidate this issue in this study. The core targets of myricetin against LUAD were screened by PharmaMapper (v2017), Assistant for Clinical Bioinformatics, STRING (v11.5) and Cytoscape (v3.8.1). Using Kaplan-Meier Plotter (v2022.04.20), UALCAN (v2021.12.13) and GEPIA (v2.0) databases, the correlation between core genes and the prognosis of LUAD patients were analyzed, and the expression levels of core genes were verified. In silico studies were used to analyze the binding energies and sites of myricetin with core genes. The effects of myricetin on H1975 cells were explored through thiazolyl blue (MTT), cell migration, colony formation and western blot assays. A total of 72 potential targets of myricetin against LUAD were identified through bioinformatics. Among the four core targets obtained by multiple networks and in silico assays, the up-regulated MMP9 (HR = 1.14 (1-1.29), logrank P = 0.046) and down-regulated PIK3R1 (HR = 0.58 (0.51-0.66), logrank P < 1E-16) were positively correlated with poor survival outcomes in LUAD patients. In vitro experiments demonstrated that myricetin inhibited the proliferation and migration of H1975 cells, promoting their apoptosis. Myricetin inhibits the proliferation of H1975 cells and induces cell apoptosis through its influence on the expression levels of MMP1, MMP3, MMP9, and PIK3R1 and regulating the multiple pathways these genes participate in. Both MMP9 and PIK3R1 are potential biomarkers for LUAD.

A p85 isoform switch enhances PI3K activation on endosomes by a MAP4- and PI3P-dependent mechanism

Phosphatidylinositol 3-kinase α (PI3Kα) is a heterodimer of p110α catalytic and p85 adaptor subunits that is activated by agonist-stimulated receptor tyrosine kinases. Although p85α recruits p110α to activated receptors on membranes, p85α loss, which occurs commonly in cancer, paradoxically promotes agonist-stimulated PI3K/Akt signaling. p110α localizes to microtubules via microtubule-associated protein 4 (MAP4), facilitating its interaction with activated receptor kinases on endosomes to initiate PI3K/Akt signaling. Here, we demonstrate that in response to agonist stimulation and p85α knockdown, the residual p110α, coupled predominantly to p85β, exhibits enhanced recruitment with receptor tyrosine kinases to endosomes. Moreover, the p110α C2 domain binds PI3-phosphate, and this interaction is also required to recruit p110α to endosomes and for PI3K/Akt signaling. Stable knockdown of p85α, which mimics the reduced p85α levels observed in cancer, enhances cell growth and tumorsphere formation, and these effects are abrogated by MAP4 or p85β knockdown, underscoring their role in the tumor-promoting activity of p85α loss.

Review of Patient Gene Profiles Obtained through a Non-Negative Matrix Factorization-Based Framework to Determine the Role Inflammation Plays in Neuroblastoma Pathogenesis

Neuroblastoma is the most common extracranial solid tumor in children. It is a highly heterogeneous tumor consisting of different subcellular types and genetic abnormalities. Literature data confirm the biological and clinical complexity of this cancer, which requires a wider availability of gene targets for the implementation of personalized therapy. This paper presents a study of neuroblastoma samples from primary tumors of untreated patients. The focus of this analysis is to evaluate the impact that the inflammatory process may have on the pathogenesis of neuroblastoma. Eighty-eight gene profiles were selected and analyzed using a non-negative matrix factorization framework to extract a subset of genes relevant to the identification of an inflammatory phenotype, whose targets (PIK3CG, NFATC2, PIK3R2, VAV1, RAC2, COL6A2, COL6A3, COL12A1, COL14A1, ITGAL, ITGB7, FOS, PTGS2, PTPRC, ITPR3) allow further investigation. Based on the genetic signals automatically derived from the data used, neuroblastoma could be classified according to stage rather than as a "cold" or "poorly immunogenic" tumor.

VHL governs m6A modification and PIK3R3 mRNA stability in clear cell renal cell carcinomas

N6-Methyladenosine (m6A), a prevalent posttranscriptional modification, plays an important role in cancer progression. Clear cell renal cell carcinoma (ccRCC) is chiefly associated with the loss of the von Hippel-Lindau (VHL) gene, encoding a component of the E3 ubiquitin ligase complex. In this issue of the JCI, Zhang and colleagues unveiled a function of VHL beyond its canonical role as an E3 ubiquitin ligase in regulating hypoxia-inducible factors (HIFs). It also governed m6A modification by orchestrating the assembly of m6A writer proteins METTL3 and METTL14, thereby stabilizing PIK3R3 mRNA. Mechanistically, PIK3R3 contributed to p85 ubiquitination, which restrained PI3K/AKT signaling and consequently impeded ccRCC growth in cell and mouse models. This discovery provides potential treatment targets in VHL-deficient ccRCCs.

Comparative genomic analysis of PIK3R1-mutated and wild-type breast cancers

PURPOSE

The PIK3R1 gene encodes the regulatory subunit-p85a-of the PI3K signaling complex. Prior studies have found that pathogenic somatic alterations in PIK3R1 are enriched in human breast cancers but the genomic landscape of breast cancer patients harboring PIK3R1 mutations has not been extensively characterized.

METHODS

We retrospectively analyzed 6,009 patient records that underwent next-generation sequencing (NGS) using the Tempus xT solid tumor assay. All patients had breast cancer with known HER2 (+/-) and hormone receptor (HR; +/-) status and were classified according to the presence of PIK3R1 mutations including short variants and copy number alterations.

RESULTS

The frequency of PIK3R1 mutations varied according to subtype: 6% in triple negative (TNBC, 89/1,475), 2% in HER2-/HR+ (80/3,893) and 2.3% in HER2+ (15/641) (p < 0.001). Co-mutations in PTEN, TP53 and NF1 were significantly enriched, co-mutations in PIK3CA were significantly less prevalent, and tumor mutational burden was significantly higher in PIK3R1-mutated HER2- samples relative to PIK3R1 wild-type. At the transcriptional-level, PIK3R1 RNA expression in HER2- disease was significantly higher in PIK3R1-mutated (excluding copy number loss) samples, regardless of subtype.

CONCLUSION

This is the largest investigation of the PIK3R1 mutational landscape in breast cancer patients (n = 6,009). PIK3R1 mutations were more common in triple-negative breast cancer (~ 6%) than in HER2 + or HER2-/HR + disease (approximately 2%). While alterations in the PI3K/AKT pathway are often actionable in HER2-/HR + breast cancer, our study suggests that PIK3R1 could be an important target in TNBC as well.

Non-catalytic role of phosphoinositide 3-kinase in mesenchymal cell migration through non-canonical induction of p85β/AP2-mediated endocytosis

Class IA phosphoinositide 3-kinase (PI3K) galvanizes fundamental cellular processes such as migration, proliferation, and differentiation. To enable these multifaceted roles, the catalytic subunit p110 utilizes the multi-domain, regulatory subunit p85 through its inter SH2 domain (iSH2). In cell migration, its product PI(3,4,5)P3 generates locomotive activity. While non-catalytic roles are also implicated, underlying mechanisms and their relationship to PI(3,4,5)P3 signaling remain elusive. Here, we report that a disordered region of iSH2 contains AP2 binding motifs which can trigger clathrin and dynamin-mediated endocytosis independent of PI3K catalytic activity. The AP2 binding motif mutants of p85 aberrantly accumulate at focal adhesions and increase both velocity and persistency in fibroblast migration. We thus propose the dual functionality of PI3K in the control of cell motility, catalytic and non-catalytic, arising distinctly from juxtaposed regions within iSH2.

Enhanced STAT3/PIK3R1/mTOR signaling triggers tubular cell inflammation and apoptosis in septic-induced acute kidney injury: implications for therapeutic intervention

Septic acute kidney injury (AKI) is a severe form of renal dysfunction associated with high morbidity and mortality rates. However, the pathophysiological mechanisms underlying septic AKI remain incompletely understood. Herein, we investigated the signaling pathways involved in septic AKI using the mouse models of lipopolysaccharide (LPS) treatment and cecal ligation and puncture (CLP). In these models, renal inflammation and tubular cell apoptosis were accompanied by the aberrant activation of the mechanistic target of rapamycin (mTOR) and the signal transducer and activator of transcription 3 (STAT3) signaling pathways. Pharmacological inhibition of either mTOR or STAT3 significantly improved renal function and reduced apoptosis and inflammation. Interestingly, inhibition of STAT3 with pharmacological inhibitors or small interfering RNA blocked LPS-induced mTOR activation in renal tubular cells, indicating a role of STAT3 in mTOR activation. Moreover, knockdown of STAT3 reduced the expression of the phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1/p85α), a key subunit of the phosphatidylinositol 3-kinase for AKT and mTOR activation. Chromatin immunoprecipitation assay also proved the binding of STAT3 to PIK3R1 gene promoter in LPS-treated kidney tubular cells. In addition, knockdown of PIK3R1 suppressed mTOR activation during LPS treatment. These findings highlight the dysregulation of mTOR and STAT3 pathways as critical mechanisms underlying the inflammatory and apoptotic phenotypes observed in renal tubular cells during septic AKI, suggesting the STAT3/ PIK3R1/mTOR pathway as a therapeutic target of septic AKI.

Transcriptome and single-cell transcriptomics reveal prognostic value and potential mechanism of anoikis in skin cutaneous melanoma

BACKGROUND

Skin cutaneous melanoma (SKCM) is a highly lethal cancer, ranking among the top four deadliest cancers. This underscores the urgent need for novel biomarkers for SKCM diagnosis and prognosis. Anoikis plays a vital role in cancer growth and metastasis, and this study aims to investigate its prognostic value and mechanism of action in SKCM.

METHODS

Utilizing consensus clustering, the SKCM samples were categorized into two distinct clusters A and B based on anoikis-related genes (ANRGs), with the B group exhibiting lower disease-specific survival (DSS). Gene set enrichment between distinct clusters was examined using Gene Set Variation Analysis (GSVA) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis.

RESULTS

We created a predictive model based on three anoikis-related differently expressed genes (DEGs), specifically, FASLG, IGF1, and PIK3R2. Moreover, the mechanism of these prognostic genes within the model was investigated at the cellular level using the single-cell sequencing dataset GSE115978. This analysis revealed that the FASLG gene was highly expressed on cluster 1 of Exhausted CD8( +) T (Tex) cells.

CONCLUSIONS

In conclusion, we have established a novel classification system for SKCM based on anoikis, which carries substantial clinical implications for SKCM patients. Notably, the elevated expression of the FASLG gene on cluster 1 of Tex cells could significantly impact SKCM prognosis through anoikis, thus offering a promising target for the development of immunotherapy for SKCM.

RNA-seq transcriptome analysis provides new insights into the negative effects of tannic acid on the intestinal function of Brandt's voles (Lasiopodomys brandtii)

Tannic acid (TA), a significant plant secondary metabolite, is contained in the daily food of Brandt's voles. Its adverse effect on gut function has been shown in earlier research, but the underlying molecular mechanisms remain uncertain. In this study, male Brandt's vole (13 weeks old) were divided into two groups and given 0 (control) or 1,200 (TA-treated) mg•kg-1 TA for 18 days. Then RNA sequencing was used to conduct a thorough transcriptome analysis on the duodenum, jejunum, and ileum of Brandt's voles. Results showed that TA significantly increased serum total cholesterol concentration (P < 0.05) and decreased the nutrient digestibility (P < 0.05) of Brandt's voles. Furthermore, there were 174 differentially expressed genes (DEGs) in the duodenum, 96 DEGs in the jejunum, and 88 DEGs in the ileum between the control and TA-treated groups. Enrichment analysis revealed that many genes associated with bile secretion, fat digestion and absorption, innate immune response, and tight junction such as ABCG2, ABCG8, PEAK1, and IFR2, etc. were altered after TA treatment, which were verified by quantitative real-time PCR. These findings suggested that TA can change the expression of intestinal genes, thereby, altering nutrition metabolism and immunological function, eventually hindering the growth of Brandt's voles. The results of this study provide a theoretical basis for explaining how TA affects the gut function of Brandt's voles at the molecular level.

Study on the material basis and action mechanisms of sophora davidii (Franch.) skeels flower extract in the treatment of non-small cell lung cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Sophora davidii (Franch.) Skeels Flower (SDF) is a characteristic folk medicine in Yunnan and Guizhou, which can be used to prevent the occurrence of tumors. The extract of SDF (SDFE) is confirmed to be antitumor by pre-experiment. However, effective components and anticancer mechanisms of SDFE are still unclear.

AIM OF THE STUDY

The purpose of this study was to explore the material basis and action mechanisms of SDFE in the treatment of non-small cell carcinoma (NSCLC).

MATERIALS AND METHODS

UHPLC-Q-Exactive-Orbitrap-MS/MS was used to identify the chemical components of SDFE. The network pharmacology was applied to screen out the main active components, core genes and related signaling pathways of SDFE in treatment of NSCLC. Molecular docking was used to predict the affinity of major components and core targets. The database was applied to predict the mRNA and protein expression levels of core targets in NSCLC. Finally, the experiments in vitro were performed by CCK-8, flow cytometry and western blot (WB).

RESULTS

In this study, 98 chemical components were identified by UHPLC-Q-Exactive- Orbitrap-MS/MS. 5 main active components (namely quercetin, genistein, luteolin, kaempferol, isorhamnetin), 10 core genes (namely TP53, AKT1, STAT3, SRC, MAPK3, EGFR, JUN, EP300, TNF, PIK3R1) and 20 pathways were screened out through network pharmacology. The 5 active ingredients were molecularly docked with the core genes, and most the LibDockScore values were higher than 100. The data collected from the database indicated that TP53, AKT1 and PIK3R1 were closely related to the occurrence of NSCLC. The results of experiment in vitro showed that SDFE promoted NSCLC cells apoptosis by down-regulating the phosphorylation of PI3K, AKT and MDM2, up-regulating the phosphorylation of P53, inhibiting the expression of Bcl-2 and up-regulating the expression of Bax.

CONCLUSION

The combination of network pharmacology, molecular docking, database validation, and in vitro experimental validation effectively demonstrates that SDFE can promote cell apoptosis by regulating PI3K-AKT/MDM2-P53 signaling pathway, so as to treat NSCLC.

Oleic Acid Exhibits Anti-Proliferative and Anti-Invasive Activities via the PTEN/AKT/mTOR Pathway in Endometrial Cancer

Reprogramming of fatty acid metabolism promotes cell growth and metastasis through a variety of processes that stimulate signaling molecules, energy storage, and membrane biosynthesis in endometrial cancer. Oleic acid is one of the most important monounsaturated fatty acids in the human body, which appears to have both pro- and anti-tumorigenic activities in various pre-clinical models. In this study, we evaluated the potential anti-tumor effects of oleic acid in endometrial cancer cells and the LKB1fl/flp53fl/fl mouse model of endometrial cancer. Oleic acid increased lipogenesis, inhibited cell proliferation, caused cell cycle G1 arrest, induced cellular stress and apoptosis, and suppressed invasion in endometrial cancer cells. Targeting of diacylglycerol acyltransferases 1 and 2 effectively increased the cytotoxicity of oleic acid. Moreover, oleic acid significantly increased the expression of wild-type PTEN, and knockdown of PTEN by shRNA partially reversed the anti-proliferative and anti-invasive effects of oleic acid. Inhibition of the AKT/mTOR pathway by ipatasertib effectively increased the anti-tumor activity of oleic acid in endometrial cancer cells. Oleic acid treatment (10 mg/kg, daily, oral) for four weeks significantly inhibited tumor growth by 52.1% in the LKB1fl/flp53fl/fl mice. Our findings demonstrated that oleic acid exhibited anti-tumorigenic activities, dependent on the PTEN/AKT/mTOR signaling pathway, in endometrial cancer.

Subconjunctival injection of human umbilical cord mesenchymal stem cells alleviates experimental allergic conjunctivitis via regulating T cell response

BACKGROUND

T helper 2 (Th2) cells are thought to play critical roles in allergic conjunctivitis (AC). They release inflammatory cytokines to promote an allergic response in AC. Due to individual heterogeneity and long-term chronic management, current therapies do not always effectively control AC. Mesenchymal stem cells (MSCs) have been shown to be effective in treating allergy-related disorders, but it is unclear how exactly the Th2-mediated allergic response is attenuated. This study aims to elucidate the therapeutic effect and mechanism of the human umbilical cord MSCs (hUCMSCs) in a mouse model of experimental AC (EAC).

METHODS

A mouse EAC model was established by inoculating short ragweed (SRW) pollen. After the SRW pollen challenge, the mice received a single subconjunctival or tail vein injection of 2 × 106 hUCMSCs, or subconjunctival injection of hUCMSCs conditioned medium (hUCMSC-CM), and dexamethasone eye drops was used as positive control; subsequent scratching behavior and clinical symptoms were assessed. Immunostaining and flow cytometry were carried out to show allergic reactions and the activation of CD4 + T cell subsets in the conjunctiva and cervical lymph nodes (CLNs). Gene expression was determined by RNA-seq and further verified by qRT-PCR and Western blot. Co-culture assays were performed to explore the regulatory role of hUCMSCs in the differentiation of CD4 + naive T cells (Th0) into Th2 cells.

RESULTS

Subconjunctival administration of hUCMSCs resulted in fewer instances of scratching and lower inflammation scores in EAC mice compared to the tail vein delivery, hUCMSC-CM and control groups. Subconjunctival administration of hUCMSCs reduced the number of activated mast cells and infiltrated eosinophils in the conjunctiva, as well as decreased the number of Th2 cells in CLNs. After pretreatment with EAC mouse serum in vitro to mimic the in vivo milieu, hUCMSCs were able to inhibit the differentiation of Th0 into Th2 cells. Further evidence demonstrated that repression of Th2 cell differentiation by hUCMSCs is mediated by CRISPLD2 through downregulation of STAT6 phosphorylation. Additionally, hUMCSCs were able to promote the differentiation of Th0 cells into regulatory T cells in CLNs of EAC mice.

CONCLUSIONS

Subconjunctival injection of hUCMSCs suppressed the Th2-allergic response and alleviated clinical symptoms. This study provides not only a potential therapeutic target for the treatment of AC but also other T cell-mediated diseases.

Development of PI3Kα inhibitors for tumor therapy

The PI3K/AKT/mTOR signaling pathway is well known to be involved in cell growth, proliferation, metabolism and other cellular physiological processes. Abnormal activation of this pathway is closely related to tumorigenesis and metastasis. As the starting node of the pathway, PI3K is known to contain 4 isoforms, including PI3Kα, a heterodimer composed of the catalytic subunit p110α and the regulatory subunit p85. PIK3CA, which encodes p110α, is frequently mutated in cancer, especially breast cancer. Abnormal activation of PI3Kα promotes cancer cell proliferation, migration, invasion, and angiogenesis; therefore, PI3Kα has become a key target for the development of anticancer drugs. The hinge region and the region of the mutation site in the PI3Kα protein are important for designing PI3Kα-specific inhibitors. As the group shared by the most PI3Kα-specific inhibitors reported thus far, carboxamide can produce hydrogen bonds with Gln859 and Ser854. Gln859 is specific to the p110α protein in producing hydrogen bond interactions with PI3Kα-specific inhibitors and this is a key point for designing PI3Kα inhibitors. To date, alpelisib is the only PI3Kα inhibitor approved for the treatment of breast cancer. Several other PI3Kα inhibitors are under evaluation in clinical trials. In this review, we briefly describe PI3Kα and its role in tumorigenesis, summarize the clinical trial results of some PI3Kα inhibitors as well as the synthetic routes of alpelisib, and finally give our proposal for the development of novel PI3Kα inhibitors for tumor therapy. HighlightsWe summarize the progress of PI3Kα and PI3Kα inhibitors in cancer from the second half of the 20th century to the present.We describe the clinical trial results of PI3Kα inhibitors as well as the synthetic routes of the only approved PI3Kα inhibitor alpelisib.Crystal structure of alpelisib bound to the PI3Kα receptor binding domain.This review gives proposal for the development of novel PI3Kα inhibitors and will serve as a complementary summary to other reviews in the research field of PI3K inhibitors.Communicated by Ramaswamy H. Sarma.

Is Insulin Receptor Substrate4 (IRS4) a Platform Involved in the Activation of Several Oncogenes?

The IRS (insulin receptor substrate) family of scaffold proteins includes insulin receptor substrate-4 (IRS4), which is expressed only in a few cell lines, including human kidney, brain, liver, and thymus and some cell lines. Its N-terminus carries a phosphotyrosine-binding (PTB) domain and a pleckstrin homology domain (PH), which distinguishes it as a member of this family. In this paper, we collected data about the molecular mechanisms that explain the relevance of IRS4 in the development of cancer and identify IRS4 differences that distinguish it from IRS1 and IRS2. Search engines and different databases, such as PubMed, UniProt, ENSEMBL and SCANSITE 4.0, were used. We used the name of the protein that it encodes "(IRS-4 or IRS4)", or the combination of these terms with the word "(cancer)" or "(human)", for searches. Terms related to specific tumor pathologies ("breast", "ovary", "colon", "lung", "lymphoma", etc.) were also used. Despite the lack of knowledge on IRS4, it has been reported that some cancers and benign tumors are characterized by high levels of IRS-4 expression. Specifically, the role of IRS-4 in different types of digestive tract neoplasms, gynecological tumors, lung cancers, melanomas, hematological tumors, and other less common types of cancers has been shown. IRS4 differs from IRS1 and IRS2 in that can activate several oncogenes that regulate the PI3K/Akt cascade, such as BRK and FER, which are characterized by tyrosine kinase-like activity without regulation via extracellular ligands. In addition, IRS4 can activate the CRKL oncogene, which is an adapter protein that regulates the MAP kinase cascade. Knowledge of the role played by IRS4 in cancers at the molecular level, specifically as a platform for oncogenes, may enable the identification and validation of new therapeutic targets.

PhenoDriver: interpretable framework for studying personalized phenotype-associated driver genes in breast cancer

Identifying personalized cancer driver genes and further revealing their oncogenic mechanisms is critical for understanding the mechanisms of cell transformation and aiding clinical diagnosis. Almost all existing methods primarily focus on identifying driver genes at the cohort or individual level but fail to further uncover their underlying oncogenic mechanisms. To fill this gap, we present an interpretable framework, PhenoDriver, to identify personalized cancer driver genes, elucidate their roles in cancer development and uncover the association between driver genes and clinical phenotypic alterations. By analyzing 988 breast cancer patients, we demonstrate the outstanding performance of PhenoDriver in identifying breast cancer driver genes at the cohort level compared to other state-of-the-art methods. Otherwise, our PhenoDriver can also effectively identify driver genes with both recurrent and rare mutations in individual patients. We further explore and reveal the oncogenic mechanisms of some known and unknown breast cancer driver genes (e.g. TP53, MAP3K1, HTT, etc.) identified by PhenoDriver, and construct their subnetworks for regulating clinical abnormal phenotypes. Notably, most of our findings are consistent with existing biological knowledge. Based on the personalized driver profiles, we discover two existing and one unreported breast cancer subtypes and uncover their molecular mechanisms. These results intensify our understanding for breast cancer mechanisms, guide therapeutic decisions and assist in the development of targeted anticancer therapies.

Omics data analysis reveals common molecular basis of small cell lung cancer and COVID-19

The impact of COVID-19 infection on individuals with small cell lung cancer (SCLC) poses a serious threat. Unfortunately, the molecular basis of this severe comorbidity has yet to be elucidated. The present study addresses this gap utilizing publicly available omics data of COVID-19 and SCLC to explore the key molecules and associated pathways involved in the convergence of these diseases. Findings revealed 402 genes, that exhibited differential expression patterns in SCLC patients and also play a pivotal role in COVID-19 pathogenesis. Subsequent functional enrichment analyses identified relevant ontologies and pathways that are significantly associated with these genes, revealing important insights into their potential biological, molecular and cellular functions. The protein-protein interaction network, constructed under four combinatorial topological assessments, highlighted SMAD3, CAV1, PIK3R1, and FN1 as the primary components to this comorbidity. Our results suggest that these components significantly regulate this cross-talk triggering the PI3K-AKT and TGF-β signaling pathways. Lastly, this study made a multi-step computational attempt and identified corylifol A and ginkgetin from natural sources that can potentially inhibit these components. Therefore, the outcomes of this study offer novel perspectives on the common molecular mechanisms underlying SCLC and COVID-19 and present future opportunities for drug development.Communicated by Ramaswamy H. Sarma.

Current status and future trends of reconstructing a vascularized tissue-engineered trachea

Alternative treatment of long tracheal defects remains one of the challenges faced by thoracic surgeons. Tissue engineering has shown great potential in addressing this regenerative medicine conundrum and the technology to make tracheal grafts using this technique is rapidly maturing, leading to unique therapeutic approaches. However, the clinical application of tissue-engineered tracheal implants is limited by insufficient revascularization. Among them, realizing the vascularization of a tissue-engineered trachea is the most challenging problem to overcome. To achieve long-term survival after tracheal transplantation, an effective blood supply must be formed to support the metabolism of seeded cells and promote tissue healing and regeneration. Otherwise, repeated infection, tissue necrosis, lumen stenosis lack of effective epithelialization, need for repeated bronchoscopy after surgery, and other complications will be inevitable and lead to graft failure and a poor outcome. Here we review and analyze various tissue engineering studies promoting angiogenesis in recent years. The general situation of reconstructing a vascularized tissue-engineered trachea, including current problems and future development trends, is elaborated from the perspectives of seed cells, scaffold materials, growth factors and signaling pathways, surgical interventions in animal models and clinical applications. This review also provides ideas and methods for the further development of better biocompatible tracheal substitutes in the future.

Network pharmacological analysis and experimental study of cucurbitacin B in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a malignant tumor with a high incidence and poor prognosis. Cucurbitacin B (CuB) is a tetracyclic triterpenoid small-molecule compound extracted from plants, such as Cucurbitaceae and Brassicaceae, which has powerful anticancer effects. However, the effect and mechanism of CuB on OSCC remain unclear. Within the framework of the current study, network pharmacology was used to analyze the relationship between CuB and OSCC. The network pharmacology analysis showed that CuB and OSCC share 134 common targets; among them, PIK3R1, SRC, STAT3, AKT1, and MAPK1 are the key targets. The molecular docking analysis showed that CuB binds five target proteins. The results of the enrichment analysis showed that CuB exerted effects on OSCC through various pathways; of these pathways, PI3K-AKT was the most important pathway. The results of the in vitro cell experiments showed that CuB could inhibit the proliferation and migration of SCC25 and CAL27 cells, block the cell cycle in the G2 phase, induce cell apoptosis, and regulate the protein expression of the PI3K-AKT signaling pathway. The results of the in vivo animal experiments showed that CuB could inhibit 4NQO-induced oral cancer in mice. Therefore, network pharmacology, molecular docking, cell experiments, and animal experiments showed that CuB could play a role in OSCC by regulating multiple targets and pathways.

The Role of PIK3R1 in Metabolic Function and Insulin Sensitivity

PIK3R1 (also known as p85α) is a regulatory subunit of phosphoinositide 3-kinases (PI3Ks). PI3K, a heterodimer of a regulatory subunit and a catalytic subunit, phosphorylates phosphatidylinositol into secondary signaling molecules involved in regulating metabolic homeostasis. PI3K converts phosphatidylinositol 4,5-bisphosphate (PIP2) to phosphatidylinositol 3,4,5-triphosphate (PIP3), which recruits protein kinase AKT to the inner leaflet of the cell membrane to be activated and to participate in various metabolic functions. PIK3R1 stabilizes and inhibits p110 catalytic activity and serves as an adaptor to interact with insulin receptor substrate (IRS) proteins and growth factor receptors. Thus, mutations in PIK3R1 or altered expression of PIK3R1 could modulate the activity of PI3K and result in significant metabolic outcomes. Interestingly, recent studies also found PI3K-independent functions of PIK3R1. Overall, in this article, we will provide an updated review of the metabolic functions of PIK3R1 that includes studies of PIK3R1 in various metabolic tissues using animal models, the mechanisms modulating PIK3R1 activity, and studies on the mutations of human PIK3R1 gene.

Mechanisms underlying the therapeutic effects of isoflavones isolated from chickpea sprouts in treating osteoporosis based on network pharmacology

Osteoporosis is a systemic bone disease that is caused by multiple factors that lead to an imbalance in bone metabolism. Isoflavones can prevent and treat osteoporosis by regulating bone metabolism through a variety of pathways. The germination of chickpeas can significantly increase their isoflavone contents. However, the use of isoflavones isolated from chickpea sprouts (ICS) to prevent and treat osteoporosis by regulating bone metabolism has not been widely studied. In vivo experimental studies in ovariectomized rats showed that ICS significantly improved femoral bone mineral density (BMD) and trabecular structure, with effects similar to raloxifene. Furthermore, the chemical composition of ICS as well as the targets and signalling pathways its regulates in the prevention and treatment of osteoporosis were predicted by network pharmacological studies. ICS with drug-like properties were identified by Lipinski's 5 principles, and intersecting targets of isoflavones with osteoporosis were identified. The overlapping targets were analysed by PPI, GO and KEGG analyses, and the possible key targets, signalling pathways and biological processes by which ICS treats osteoporosis were predicted; the prediction results were verified by molecular docking technology. The results showed that ICS could play an important role in the treatment of osteoporosis through "multicomponent, multitarget and multipathway" mechanisms, and the MAKP, NF-kB and ER-related signalling pathways may be important pathways by which ICS regulates osteoporosis; these findings provide a new theoretical basis for further experimental studies.

Bioinformatics identification and validation of aging‑related molecular subtype and prognostic signature in breast cancer

Patients with metastatic breast cancer have a poor clinical outcome, accounting for more than 90 percent of breast cancer-related deaths. Aging could regulate many biological processes in malignancies by regulating cell senescence. The role of aging has not been fully clarified. Consensus cluster analysis was performed to differentiate The Cancer Genome Atlas (TCGA) breast cancer cases. Least absolute shrinkage and selection operator (LASSO) cox regression analysis was performed to construct an aging-related prognostic signature. A total of 118 differentially expressed aging-related genes (ARGs) was obtained in breast cancer. Consensus clustering analysis identified 3 categories of TCGA-breast cancer with significant difference in prognosis and immune infiltration. We also constructed an aging-related prognostic signature for breast cancer, which had a good performance in predicting the 1-year, 3-year and 5-year OS and disease specific survival (DSS) of breast cancer patients. Further single gene analysis revealed that the expression of PIK3R1 was significantly different in different pT and pN stages of breast cancer. Moreover, low expression of PIK3R1 showed resistance to many drugs based on the data of Genomics of Drug Sensitivity in Cancer (GDSC) and Genomics of Therapeutics Response Portal (CTRP). PIK3R1 played a vital role in many well-known cancer-related pathways. The current study identified 3 clusters of TCGA-breast cancer cases with significant differences in prognosis and immune infiltration. We also constructed an aging-related prognostic signature for breast cancer. However, further in vivo and in vitro studies should be conducted to verify these results.

Non-catalytic role of phosphoinositide 3-kinase in mesenchymal cell migration through non-canonical induction of p85β/AP-2-mediated endocytosis

Class IA phosphoinositide 3-kinase (PI3K) galvanizes fundamental cellular processes such as migration, proliferation, and differentiation. To enable multifaceted roles, the catalytic subunit p110 utilizes a multi-domain, regulatory subunit p85 through its inter SH2 domain (iSH2). In cell migration, their product PI(3,4,5)P3 generates locomotive activity. While non-catalytic roles are also implicated, underlying mechanisms and its relationship to PI(3,4,5)P3 signaling remain elusive. Here, we report that a disordered region of iSH2 contains previously uncharacterized AP-2 binding motifs which can trigger clathrin and dynamin-mediated endocytosis independent of PI3K catalytic activity. The AP-2 binding motif mutants of p85 aberrantly accumulate at focal adhesions and upregulate both velocity and persistency in fibroblast migration. We thus propose the dual functionality of PI3K in the control of cell motility, catalytic and non-catalytic, arising distinctly from juxtaposed regions within iSH2.

Oncogenic mutations of PIK3CA lead to increased membrane recruitment driven by reorientation of the ABD, p85 and C-terminus

PIK3CA encoding the phosphoinositide 3-kinase (PI3K) p110α catalytic subunit is frequently mutated in cancer, with mutations occurring widely throughout the primary sequence. The full set of mechanisms underlying how PI3Ks are activated by all oncogenic mutations on membranes are unclear. Using a synergy of biochemical assays and hydrogen deuterium exchange mass spectrometry (HDX-MS), we reveal unique regulatory mechanisms underlying PI3K activation. Engagement of p110α on membranes leads to disengagement of the ABD of p110α from the catalytic core, and the C2 domain from the iSH2 domain of the p85 regulatory subunit. PI3K activation also requires reorientation of the p110α C-terminus, with mutations that alter the inhibited conformation of the C-terminus increasing membrane binding. Mutations at the C-terminus (M1043I/L, H1047R, G1049R, and N1068KLKR) activate p110α through distinct mechanisms, with this having important implications for mutant selective inhibitor development. This work reveals unique mechanisms underlying how PI3K is activated by oncogenic mutations, and explains how double mutants can synergistically increase PI3K activity.

Non-catalytic role of phosphoinositide 3-kinase in mesenchymal cell migration through non-canonical induction of p85β/AP-2-mediated endocytosis

Class IA phosphoinositide 3-kinase (PI3K) galvanizes fundamental cellular processes such as migration, proliferation, and differentiation. To enable multifaceted roles, the catalytic subunit p110 utilizes a multidomain, regulatory subunit p85 through its inter SH2 domain (iSH2). In cell migration, their product PI(3,4,5)P3 generates locomotive activity. While non-catalytic roles are also implicated, underlying mechanisms and its relationship to PI(3,4,5)P3 signaling remain elusive. Here, we report that a disordered region of iSH2 contains previously uncharacterized AP-2 binding motifs which can trigger clathrin and dynamin-mediated endocytosis independent of PI3K catalytic activity. The AP-2 binding motif mutants of p85 aberrantly accumulate at focal adhesions and upregulate both velocity and persistency in fibroblast migration. We thus propose the dual functionality of PI3K in the control of cell motility, catalytic and non-catalytic, arising distinctly from juxtaposed regions within iSH2.

Comprehensive transcriptomic profiling and mutational landscape of primary gastric linitis plastica

BACKGROUND

Primary gastric linitis plastica (GLP) is a distinct phenotype of gastric cancer with poor survival. Comprehensive molecular profiles and putative therapeutic targets of GLP remain undetermined.

METHODS

We subjected 10 tumor-normal tissue pairs to whole exome sequencing (WES) and whole transcriptome sequencing (WTS). 10 tumor samples were all GLP which involves 100% of the gastric wall macroscopically. TCGA data were compared to generate the top mutated genes and the overexpressed genes in GLP.

RESULTS

Our results reveal that GLP has distinctive genomic and transcriptomic features, dysfunction in the Hippo pathway is likely to be a key step during GLP development. 6 genes were identified as significantly highly mutated genes in GLP, including AOX1, ANKRD36C, CPXM1, PTPN14, RPAP1, and DCDC1). MUC6, as a previously identified gastric cancer driver gene, has a high mutation rate (20%) in GLP. 20% of patients in our GLP cohort had CDH1 mutations, while none had RHOA mutations. GLP exhibits high immunodeficiency and low AMPK pathway activity. Our WTS results showed that 3 PI3K-AKT pathway-related genes (PIK3R2, AKT3, and IGF1) were significantly up-regulated in GLP. Two genes were identified using immunohistochemistry (IHC), IGF2BP3 and MUC16, which specifically expressed in diffuse-type-related gastric cancer cell lines, and its knockdown inhibits PI3K-AKT pathway activity.

CONCLUSIONS

We provide the first integrative genomic and transcriptomic profiles of GLP, which may facilitate its diagnosis, prognosis, and treatment.

Mechanism and function of miR-140 in human cancers: A review and in silico study

MicroRNA-140 (miR-140) acts as a tumor suppressor and plays a vital role in cell biological functions such as cell proliferation, apoptosis, and DNA repair. The expression of this miRNA has been shown to be considerably decreased in cancer tissues and cell lines compared with normal adjacent tissues. Consequently, aberrant expression of some miR-140 target genes can lead to the initiation and progression of various human cancers, such as breast cancer, gastrointestinal cancers, lung cancer, and prostate cancer. The dysregulation of the miR-140 network also affects cell proliferation, invasion, metastasis, and apoptosis of cancer cells by affecting various signaling pathways. Besides, up-regulation of miR-140 could enhance the efficacy of chemotherapeutic agents in different cancer. We aimed to cover most aspects of miR-140 function in cancer development and address its importance in different stages of cancer progression.

Elucidating the mechanism of Hongjinshen decoction in the treatment of pulmonary fibrosis based on network pharmacology and molecular docking

BACKGROUND

To explore the mechanism of compound Hongginshen decoction in improving pulmonary fibrosis based on network pharmacology.

METHODS

The active components and targets of ginseng and Salvia miltiorrhiza were screened from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) database. The chemical components of Rhodiola, Ophiopogon japonicus, and Dendrobium were screened using the Traditional Chinese Medicine Integrated Database (TCMID), and the target compounds were predicted by the Swisstargets method. The related target genes of pulmonary fiber (PF) were screened by the Genecards database and the National Center of Biotechnology Information (NCBI) database. The protein-protein interaction network was drawn using the string database and Cytoscape software, and the network topology was analyzed. Then, using R3.6.3 software, biological processes, molecular function, cell component enrichment, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment were carried out on the common targets of drugs and diseases. The network diagram of the "traditional Chinese medicine composition disease target" of Compound Hongginshen Decoction was constructed and analyzed with the software of Cytoscape 3.6.1.

RESULTS

We identified 159 active components and 2820 targets in Compound Hongginshen Decoction, and 2680 targets in pulmonary fibrosis. A total of 343 common targets were obtained by the intersection of drug targets and disease targets. protein-protein interaction protein interaction network analysis showed that PIK3CA, PIK3R1, MAPK1, SRC, AKT1, and so on may be the core targets of the compound Hongjingshen recipe in the treatment of pulmonary fibrosis. Gene Ontology (GO) enrichment analysis identified 3463 items, and KEGG pathway enrichment analysis identified 181 related signaling pathways, including the PI3K-Akt signaling pathway, HCMV pathway, Hb pathway, PGs pathway, and KSHV signaling pathway.

CONCLUSION

Compound Hongginshen Decoction has the characteristics of a multichannel and multitargeted effect in the treatment of pulmonary fibrosis. Radix Ophiopogonis and Dendrobium officinale play a key role in the treatment of pulmonary fibrosis. The whole compound prescription may play a therapeutic role by affecting cell metabolism, being anti-inflammatory, regulating the immune system, promoting angiogenesis, and improving anaerobic metabolism.

Targeting TROY-mediated P85a/AKT/TBX3 signaling attenuates tumor stemness and elevates treatment response in hepatocellular carcinoma

Background

Previous in vitro hepatocyte differentiation model showed that TROY was specifically expressed in liver progenitor cells and a small proportion of hepatocellular carcinoma cells, suggesting that TROY may participate in hepatocellular carcinoma (HCC) stemness regulation. Here, we aim to investigate the role and mechanism of TROY in HCC pathogenesis.

Method

Bioinformatics analysis of the TCGA dataset has been used to identify the function and mechanism of TROY. Spheroid, apoptosis, and ALDH assay were performed to evaluate the stemness functions. Validation of the downstream pathway was based on Western blot, co-immunoprecipitation, and double immunofluorescence.

Results

HCC tissue microarray study found that a high frequency of TROY-positive cells was detected in 53/130 (40.8%) of HCC cases, which was significantly associated with poor prognosis and tumor metastasis. Functional studies revealed that TROY could promote self-renewal, drug resistance, tumorigenicity, and metastasis of HCC cells. Mechanism study found that TROY could interact with PI3K subunit p85α, inducing its polyubiquitylation and degradation. The degradation of p85α subsequently activate PI3K/AKT/TBX3 signaling and upregulated pluripotent genes expression including SOX2, NANOG, and OCT4, and promoted EMT in HCC cells. Interestingly, immune cell infiltration analysis found that upregulation of TROY in HCC tissues was induced by TGF-β1 secreted from CAFs. PI3K inhibitor wortmannin could effectively impair tumor stemness to sorafenib.

Conclusion

We demonstrated that TROY is an HCC CSC marker and plays an important role in HCC stemness regulation. Targeting TROY-positive CSCs with PI3K inhibitor wortmannin combined with chemo- or targeted drugs might be a novel therapeutic strategy for HCC patients.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02401-6.

Progress in the studies on the molecular mechanisms associated with multidrug resistance in cancers

Chemotherapy is one of the important methods to treat cancer, and the emergence of multidrug resistance (MDR) is one major cause for the failure of cancer chemotherapy. Almost all anti-tumor drugs develop drug resistance over a period of time of application in cancer patients, reducing their effects on killing cancer cells. Chemoresistance can lead to a rapid recurrence of cancers and ultimately patient death. MDR may be induced by multiple mechanisms, which are associated with a complex process of multiple genes, factors, pathways, and multiple steps, and today the MDR-associated mechanisms are largely unknown. In this paper, from the aspects of protein-protein interactions, alternative splicing (AS) in pre-mRNA, non-coding RNA (ncRNA) mediation, genome mutations, variance in cell functions, and influence from the tumor microenvironment, we summarize the molecular mechanisms associated with MDR in cancers. In the end, prospects for the exploration of antitumor drugs that can reverse MDR are briefly discussed from the angle of drug systems with improved targeting properties, biocompatibility, availability, and other advantages.

Mechanism underlying circRNA dysregulation in the TME of digestive system cancer

Circular RNAs (circRNAs) are a new series of noncoding RNAs (ncRNAs) that have been reported to be expressed in eukaryotic cells and have a variety of biological functions in the regulation of cancer pathogenesis and progression. The TME, as a microscopic ecological environment, consists of a variety of cells, including tumor cells, immune cells and other normal cells, ECM and a large number of signaling molecules. The crosstalk between circRNAs and the TME plays a complicated role in affecting the malignant behaviors of digestive system cancers. Herein, we summarize the mechanisms underlying aberrant circRNA expression in the TME of the digestive system cancers, including immune surveillance, angiogenesis, EMT, and ECM remodelling. The regulation of the TME by circRNA is expected to be a new therapeutic method.

Co-administration of MDR1 and BCRP or EGFR/PI3K inhibitors overcomes lenvatinib resistance in hepatocellular carcinoma

Lenvatinib is the first-line treatment for hepatocellular carcinoma (HCC), the most common type of primary liver cancer; however, some patients become refractory to lenvatinib. The underlying mechanism of lenvatinib resistance (LR) in patients with advanced HCC remains unclear. We focused on exploring the potential mechanism of LR and novel treatments of lenvatinib-resistant HCC. In particular, we established a Huh7 LR cell line and performed in vitro, bioinformatic, and biochemical assays. Additionally, we used a Huh7-LR cell-derived xenograft mouse model to confirm the results in vivo. Following LR induction, multidrug resistance protein 1 (MDR1) and breast cancer resistance protein (BCRP) transporters were markedly upregulated, and the epidermal growth factor receptor (EGFR), MEK/ERK, and PI3K/AKT pathways were activated. In vitro, the co-administration of elacridar, a dual MDR1 and BCRP inhibitor, with lenvatinib inhibited proliferation and induced apoptosis of LR cells. These effects might be due to inhibiting cancer stem-like cells (CSCs) properties, by decreasing colony formation and downregulating CD133, EpCAM, SOX-9, and c-Myc expression. Moreover, the co-administration of gefitinib, an EGFR inhibitor, with lenvatinib retarded proliferation and induced apoptosis of LR cells. These similar effects might be caused by the inhibition of EGFR-mediated MEK/ERK and PI3K/AKT pathway activation. In vivo, co-administration of lenvatinib with elacridar or gefitinib suppressed tumour growth and angiogenesis. Therefore, inhibiting MDR1 and BCRP transporters or targeting the EGFR/PI3K pathway might overcome LR in HCC. Notably, lenvatinib should be used to treat HCC after LR induction owing to its role in inhibiting tumour proliferation and angiogenesis. Our findings could help develop novel and effective treatment strategies for HCC.

Identification of circRNA–miRNA–mRNA Regulatory Network and Crucial Signaling Pathway Axis Involved in Tetralogy of Fallot

Tetralogy of Fallot (TOF) is one of the most common cyanotic congenital heart diseases (CHD) worldwide; however, its pathogenesis remains unclear. Recent studies have shown that circular RNAs (circRNAs) act as “sponges” for microRNAs (miRNAs) to compete for endogenous RNA (ceRNA) and play important roles in regulating gene transcription and biological processes. However, the mechanism of ceRNA in TOF remains unclear. To explore the crucial regulatory connections and pathways of TOF, we obtained the human TOF gene, miRNA, and circRNA expression profiling datasets from the Gene Expression Omnibus (GEO) database. After data pretreatment, differentially expressed mRNAs (DEmRNAs), microRNAs (DEmiRNAs), and circRNAs (DEcircRNAs) were identified between the TOF and healthy groups, and a global triple ceRNA regulatory network, including circRNAs, miRNAs, and mRNAs based on the integrated data, was constructed. A functional enrichment analysis was performed on the Metascape website to explore the biological functions of the selected genes. Then, we constructed a protein-protein interaction (PPI) network and identified seven hub genes using the cytoHubba and MCODE plug-ins in the Cytoscape software, including BCL2L11, PIK3R1, SOCS3, OSMR, STAT3, RUNX3, and IL6R. Additionally, a circRNA–miRNA–hub gene subnetwork was established, and its enrichment analysis results indicated that the extrinsic apoptotic signaling pathway, JAK-STAT signaling pathway and PI3K-Akt signaling pathway may be involved in the pathogenesis of TOF. We further identified the hsa_circ_000601/hsa-miR-148a/BCL2L11 axis as a crucial signaling pathway axis from the subnetwork. This study provides a novel regulatory network for the pathogenesis of TOF, revealing the possible molecular mechanisms and crucial regulatory pathways that may provide new strategies for candidate diagnostic biomarkers or potential therapeutic targets for TOF.

Taohong Siwu Decoction exerts anticancer effects on breast cancer via regulating MYC, BIRC5, EGF and PIK3R1 revealed by HTS2 technology

Taohong Siwu Decoction (TSD), a classical gynecological prescription that was firstly reported 600 years ago, has been widely used in the adjuvant treatment of breast cancer (BRCA) in China. However, the mechanism of action of TSD in treating BRCA has remained unclear. Here, high-throughput sequencing-based high-throughput screening (HTS²) technology was used to reveal the molecular mechanism of TSD, combination with bioinformatics and systems pharmacology in this study. Firstly, our results showed that TSD exerts an anticancer effect on BRCA cells by inhibiting cell proliferation, migration and inducing apoptosis as well as cell-cycle arrest. And our results from HTS² suggested that herbs of TSD could significantly inhibit KRAS pathway and pathway in cancer, and activate apoptosis pathway, p53 pathway and hypoxia pathway, which may lead to the anticancer function of TSD. Further, we found that TSD clearly regulates MYC, BIRC5, EGF, and PIK3R1 genes, which play an important role in the development and progression of tumor and have significant correlation with overall survival in BRCA patients. By molecular docking, we discovered that Pentagalloylglucose, a compound derived from TSD, might directly bind to and inhibit the function of BRD4, which is a reported transcriptional activator of MYC gene, and thus repress the expression of MYC. Taken together, this study explores the mechanism of TSD in anti-BRCA by combining HTS² technology, bioinformatics analysis and systems pharmacology.

The genomic landscape of cholangiocarcinoma reveals the disruption of post-transcriptional modifiers

Molecular variation between geographical populations and subtypes indicate potential genomic heterogeneity and novel genomic features within CCA. Here, we analyze exome-sequencing data of 87 perihilar cholangiocarcinoma (pCCA) and 261 intrahepatic cholangiocarcinoma (iCCA) cases from 3 Asian centers (including 43 pCCAs and 24 iCCAs from our center). iCCA tumours demonstrate a higher tumor mutation burden and copy number alteration burden (CNAB) than pCCA tumours, and high CNAB indicates a poorer pCCA prognosis. We identify 12 significantly mutated genes and 5 focal CNA regions, and demonstrate common mutations in post-transcriptional modification-related potential driver genes METTL14 and RBM10 in pCCA tumours. Finally we demonstrate the tumour-suppressive role of METTL14, a major RNA N6-adenosine methyltransferase (m6A), and illustrate that its loss-of-function mutation R298H may act through m6A modification on potential driver gene MACF1. Our results may be valuable for better understanding of how post-transcriptional modification can affect CCA development, and highlight both similarities and differences between pCCA and iCCA.

Cholangiocarcinoma is a heterogenous group of cancers, with large genetic variation seen within subtypes. Here, the authors find 12 significantly mutated genes and 5 focal CNA regions were found in perihilar cholangiocarcinoma, and identified METTL14 to have a potential tumour suppressive role.

LncRNA XLOC013218 promotes cell proliferation and TMZ resistance by targeting PIK3R2-mediated PI3K/AKT pathway in glioma

The discovery of long non-coding RNAs (lncRNAs) has improved the understanding of development and progression in various cancer sub-types. However, the role of lncRNAs in temozolomide (TMZ) resistance in glioblastoma (GBM) remains largely undefined. In this present study, the differential expression of lncRNAs were identified between U87 and U87TR (TMZ-resistant) cells. LncRNA XLOC013218 (XLOC) was drastically upregulated in TMZ-resistant cells and was associated with poor prognosis in glioma. Overexpression of XLOC markedly increased TMZ resistance, promoted proliferation, and inhibited apoptosis in vitro and in vivo. In addition, RNA-seq analysis and gain-of-function or loss-of-function studies revealed that PIK3R2 was the potential target of XLOC. Mechanistically, XLOC recruited Specificity Protein 1 (Sp1) transcription factor and promoted the binding of Sp1 to the promoters of PIK3R2, which elevated the expression of PIK3R2 in both mRNA and protein levels. Finally, PIK3R2-mediated activation of the PI3K/AKT signaling pathway promoted TMZ resistance and cell proliferation, but inhibited cell apoptosis. In conclusion, these data highlight the vital role of XLOC/Sp1/PIK3R2/PI3K/AKT axis in GBM TMZ resistance.

FER-mediated phosphorylation and PIK3R2 recruitment on IRS4 promotes AKT activation and tumorigenesis in ovarian cancer cells

Tyrosine phosphorylation, orchestrated by tyrosine kinases and phosphatases, modulates a multi-layered signaling network in a time- and space-dependent manner. Dysregulation of this post-translational modification is inevitably associated with pathological diseases. Our previous work has demonstrated that non-receptor tyrosine kinase FER is upregulated in ovarian cancer, knocking down which attenuates metastatic phenotypes. However, due to the limited number of known substrates in the ovarian cancer context, the molecular basis for its pro-proliferation activity remains enigmatic. Here, we employed mass spectrometry and biochemical approaches to identify insulin receptor substrate 4 (IRS4) as a novel substrate of FER. FER engaged its kinase domain to associate with the PH and PTB domains of IRS4. Using a proximity-based tagging system in ovarian carcinoma-derived OVCAR-5 cells, we determined that FER-mediated phosphorylation of Tyr779 enables IRS4 to recruit PIK3R2/p85β, the regulatory subunit of PI3K, and activate the PI3K-AKT pathway. Rescuing IRS4-null ovarian tumor cells with phosphorylation-defective mutant, but not WT IRS4 delayed ovarian tumor cell proliferation both in vitro and in vivo. Overall, we revealed a kinase-substrate mode between FER and IRS4, and the pharmacological inhibition of FER kinase may be beneficial for ovarian cancer patients with PI3K-AKT hyperactivation.

Systematic review and meta-analysis of genomic alterations in acral melanoma

Acral melanoma (AM) tumors arise on the palms, soles, fingers, toes, and nailbeds. A comprehensive systematic meta-analysis of AM genomic aberrations has not been conducted to date. A literature review was carried out to identify studies sequencing AM. Whole-genome/exome data from 181 samples were identified. Targeted panel sequencing data from MSK-IMPACT were included as a validation cohort (n = 92), and studies using targeted hot spot sequencing were also collated for BRAF (n = 26 studies), NRAS (n = 21), and KIT (n = 32). Statistical analysis indicated BRAF, NRAS, PTEN, TYRP1, and KIT as significantly mutated genes. Frequent copy-number aberrations were also found for important cancer genes, such as CDKN2A, KIT, MDM2, CCND1, CDK4, and PAK1, among others. Mapping genomic alterations within the context of the hallmarks of cancer identified four components frequently altered, including (i) sustained proliferative signaling and (ii) evading growth suppression, (iii) genome instability and mutation, and (iv) enabling replicative immortality. This analysis provides the largest analysis of genomic aberrations in AM in the literature to date and highlights pathways that may be therapeutically targetable.

TMT-based proteomics analysis of the cerebral cortex of TauT knockout rats

Background

Taurine serves a variety of nutritional and physiological roles, and it is mostly transported in cells via taurine transporter (TauT). The effect of taurine transporter in cerebral cortex is still unknown. We employed TMT label-based proteomics to find differences in proteins in the cerebral cortex of TauT knockout rats in this investigation. The goal of this research was to see how TauT deletion affected protein alterations in brain tissue and to see if there was a new research area for TauT.

Methods

The cerebral cortex of TauT knockout rats and wild-type control rats were analyzed using TMT-based proteomics, and differentially expressed proteins were analyzed by bioinformatics analysis means such as GO and KEGG, the association between the proteins was found by PPI, and biologically significant and interesting proteins were selected for verification by WB and immunohistochemistry.

Results

There were total of 8275 proteins found, but only 35 differentially expressed proteins were identified (27 up-regulated and 8 down-regulated), and gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to predict the biological pathways and functional classification of the proteins. The results show that these differentially expressed proteins are mainly enriched in lysine degradation, cell cycle, chronic myeloid leukemia, and longevity regulating pathways-multiple species, renal cell carcinoma, pathways in cancer, etc. To verify the proteomic data, we analyzed the expression of Annexin6 and Pik3r2 by western blotting and immunofluorescence. The results are consistent with proteomics, which proves the reliability of our proteomics data.

Conclusion

Through TMT-based proteomics, we have a comprehensive understanding of the effect of TauT knockout on the changes of other proteins in the cerebral cortex, providing new evidence for further understanding the function of TauT.

CDK6-PI3K signaling axis is an efficient target for attenuating ABCB1/P-gp mediated multi-drug resistance (MDR) in cancer cells

BACKGROUND

Multidrug resistance (MDR) mediated by ATP binding cassette subfamily B member 1 (ABCB1/P-gp) is a major cause of cancer chemotherapy failure, but the regulation mechanisms are largely unknown.

METHODS

Based on single gene knockout, we studied the regulation of CDK6-PI3K axis on ABCB1-mediated MDR in human cancer cells. CRISPR/Cas9 technique was performed in KB-C2 cells to knockout cdk6 or cdk4 gene. Western blot, RT-PCR and transcriptome analysis were performed to investigate target gene deletion and expression of critical signaling factors. The effect of cdk4 or cdk6 deficiency on cell apoptosis and the cell cycle was analyzed using flow cytometry. In vivo studies were performed to study the sensitivity of KB-C2 tumors to doxorubicin, tumor growth and metastasis.

RESULTS

Deficiency of cdk6 led to remarkable downregulation of ABCB1 expression and reversal of ABCB1-mediated MDR. Transcriptomic analysis revealed that CDK6 knockout regulated a series of signaling factors, among them, PI3K 110α and 110β, KRAS and MAPK10 were downregulated, and FOS-promoting cell autophagy and CXCL1-regulating multiple factors were upregulated. Notably, PI3K 110α/110β deficiency in-return downregulated CDK6 and the CDK6-PI3K axis synergizes in regulating ABCB1 expression, which strengthened the regulation of ABCB1 over single regulation by either CDK6 or PI3K 110α/110β. High frequency of alternative splicing (AS) of premature ABCB1 mRNA induced by CDK6, CDK4 or PI3K 110α/110β level change was confirmed to alter the ABCB1 level, among them 10 common skipped exon (SE) events were found. In vivo experiments demonstrated that loss of cdk6 remarkably increased the sensitivity of KB-C2 tumors to doxorubicin by increasing drug accumulation of the tumors, resulting in remarkable inhibition of tumor growth and metastasis, as well as KB-C2 survival in the nude mice.

CONCLUSIONS

CDK6-PI3K as a new target signaling axis to reverse ABCB1-mediated MDR is reported for the first time in cancers. Pathways leading to inhibition of cancer cell proliferation were revealed to be accompanied by CDK6 deficiency.

Nuclear translocation of p85β promotes tumorigenesis of PIK3CA helical domain mutant cancer

PI3Ks consist of p110 catalytic subunits and p85 regulatory subunits. PIK3CA, encoding p110α, is frequently mutated in human cancers. Most PIK3CA mutations are clustered in the helical domain or the kinase domain. Here, we report that p85β disassociates from p110α helical domain mutant protein and translocates into the nucleus through a nuclear localization sequence (NLS). Nuclear p85β recruits deubiquitinase USP7 to stabilize EZH1 and EZH2 and enhances H3K27 trimethylation. Knockout of p85β or p85β NLS mutant reduces the growth of tumors harboring a PIK3CA helical domain mutation. Our studies illuminate a novel mechanism by which PIK3CA helical domain mutations exert their oncogenic function. Finally, a combination of Alpelisib, a p110α-specific inhibitor, and an EZH inhibitor, Tazemetostat, induces regression of xenograft tumors harboring a PIK3CA helical domain mutation, but not tumors with either a WT PIK3CA or a PIK3CA kinase domain mutation, suggesting that the drug combination could be an effective therapeutic approach for PIK3CA helical domain mutant tumors.

The mechanisms behind the oncogenic role of the PIK3CA helical domain mutant is poorly understood. Here, the authors show that its oncogenic function depends on the release of p85β from mutated p110α, its translocation to the nucleus and the consequent increased activity of EZH proteins.

Pan-cancer analysis on the role of PIK3R1 and PIK3R2 in human tumors

Phosphoinositide-3-Kinase Regulatory Subunit 1 (PIK3R1) is believed to function as a tumor suppressor, while Phosphoinositide-3-Kinase Regulatory Subunit 2 (PIK3R2) as a tumor driver. However, there is no systematic pan-cancer analysis of them. The pan-cancer study comprehensively investigated the gene expression, genetic alteration, DNA methylation, and prognostic significance of PIK3R1 and PIK3R2 in 33 different tumors based on the TIMER, GEPIA, UALCAN, HPA, cBioPortal, and Kaplan-Meier Plotter database. The results indicated that PIK3R1 is lowly expressed in most tumors while PIK3R2 is highly expressed in most tumors, and abnormal gene expression may be related to promoter methylation. Moreover, not only mutations, downregulation of PIK3R1 and upregulation of PIK3R2 were found to be detrimental to the survival of most cancer patients as well. Furthermore, the expression of both PIK3R1 and PIK3R2 was associated with the level of immune infiltration in multiple tumors, such as breast invasive carcinoma. Our study conducted a comparatively comprehensive analysis of the role of PIK3R1 and PIK3R2 in a variety of cancers, contributing to further study of their potential mechanisms in cancer occurrence and progression. Our findings suggested that PIK3R1 and PIK3R2 could serve as prognostic markers for several cancers.